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Posted to commits@zeppelin.apache.org by jo...@apache.org on 2018/08/29 10:07:39 UTC

[43/50] [abbrv] zeppelin git commit: Revert "[ZEPPELIN-3740] Adopt `google-java-format` and `fmt-maven-plugin`"

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/BaseLivyInterpreter.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/BaseLivyInterpreter.java b/livy/src/main/java/org/apache/zeppelin/livy/BaseLivyInterpreter.java
index 4c21136..95674ea 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/BaseLivyInterpreter.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/BaseLivyInterpreter.java
@@ -20,22 +20,7 @@ package org.apache.zeppelin.livy;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.annotations.SerializedName;
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.nio.charset.Charset;
-import java.security.KeyStore;
-import java.security.Principal;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Properties;
-import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-import javax.net.ssl.SSLContext;
+
 import org.apache.commons.lang.StringUtils;
 import org.apache.commons.lang.exception.ExceptionUtils;
 import org.apache.http.auth.AuthSchemeProvider;
@@ -53,13 +38,6 @@ import org.apache.http.impl.auth.SPNegoSchemeFactory;
 import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.impl.client.HttpClients;
-import org.apache.zeppelin.interpreter.Interpreter;
-import org.apache.zeppelin.interpreter.InterpreterContext;
-import org.apache.zeppelin.interpreter.InterpreterException;
-import org.apache.zeppelin.interpreter.InterpreterResult;
-import org.apache.zeppelin.interpreter.InterpreterResultMessage;
-import org.apache.zeppelin.interpreter.InterpreterUtils;
-import org.apache.zeppelin.interpreter.thrift.InterpreterCompletion;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.http.HttpEntity;
@@ -75,7 +53,35 @@ import org.springframework.web.client.HttpServerErrorException;
 import org.springframework.web.client.RestClientException;
 import org.springframework.web.client.RestTemplate;
 
-/** Base class for livy interpreters. */
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.security.KeyStore;
+import java.security.Principal;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import javax.net.ssl.SSLContext;
+
+import org.apache.zeppelin.interpreter.Interpreter;
+import org.apache.zeppelin.interpreter.InterpreterContext;
+import org.apache.zeppelin.interpreter.InterpreterException;
+import org.apache.zeppelin.interpreter.InterpreterResult;
+import org.apache.zeppelin.interpreter.InterpreterResultMessage;
+import org.apache.zeppelin.interpreter.InterpreterUtils;
+import org.apache.zeppelin.interpreter.thrift.InterpreterCompletion;
+
+/**
+ * Base class for livy interpreters.
+ */
 public abstract class BaseLivyInterpreter extends Interpreter {
 
   protected static final Logger LOGGER = LoggerFactory.getLogger(BaseLivyInterpreter.class);
@@ -96,34 +102,32 @@ public abstract class BaseLivyInterpreter extends Interpreter {
   // delegate to sharedInterpreter when it is available
   protected LivySharedInterpreter sharedInterpreter;
 
-  Set<Object> paragraphsToCancel =
-      Collections.newSetFromMap(new ConcurrentHashMap<Object, Boolean>());
+  Set<Object> paragraphsToCancel = Collections.newSetFromMap(
+      new ConcurrentHashMap<Object, Boolean>());
   private ConcurrentHashMap<String, Integer> paragraphId2StmtProgressMap =
       new ConcurrentHashMap<>();
 
   public BaseLivyInterpreter(Properties property) {
     super(property);
     this.livyURL = property.getProperty("zeppelin.livy.url");
-    this.displayAppInfo =
-        Boolean.parseBoolean(property.getProperty("zeppelin.livy.displayAppInfo", "true"));
-    this.restartDeadSession =
-        Boolean.parseBoolean(property.getProperty("zeppelin.livy.restart_dead_session", "false"));
-    this.sessionCreationTimeout =
-        Integer.parseInt(property.getProperty("zeppelin.livy.session.create_timeout", 120 + ""));
-    this.pullStatusInterval =
-        Integer.parseInt(
-            property.getProperty("zeppelin.livy.pull_status.interval.millis", 1000 + ""));
-    this.maxLogLines = Integer.parseInt(property.getProperty("zeppelin.livy.maxLogLines", "1000"));
+    this.displayAppInfo = Boolean.parseBoolean(
+        property.getProperty("zeppelin.livy.displayAppInfo", "true"));
+    this.restartDeadSession = Boolean.parseBoolean(
+        property.getProperty("zeppelin.livy.restart_dead_session", "false"));
+    this.sessionCreationTimeout = Integer.parseInt(
+        property.getProperty("zeppelin.livy.session.create_timeout", 120 + ""));
+    this.pullStatusInterval = Integer.parseInt(
+        property.getProperty("zeppelin.livy.pull_status.interval.millis", 1000 + ""));
+    this.maxLogLines = Integer.parseInt(property.getProperty("zeppelin.livy.maxLogLines",
+        "1000"));
     this.restTemplate = createRestTemplate();
     if (!StringUtils.isBlank(property.getProperty("zeppelin.livy.http.headers"))) {
       String[] headers = property.getProperty("zeppelin.livy.http.headers").split(";");
       for (String header : headers) {
         String[] splits = header.split(":", -1);
         if (splits.length != 2) {
-          throw new RuntimeException(
-              "Invalid format of http headers: "
-                  + header
-                  + ", valid http header format is HEADER_NAME:HEADER_VALUE");
+          throw new RuntimeException("Invalid format of http headers: " + header +
+              ", valid http header format is HEADER_NAME:HEADER_VALUE");
         }
         customHeaders.put(splits[0].trim(), envSubstitute(splits[1].trim()));
       }
@@ -159,8 +163,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
         initLivySession();
       }
     } catch (LivyException e) {
-      String msg =
-          "Fail to create session, please check livy interpreter log and " + "livy server log";
+      String msg = "Fail to create session, please check livy interpreter log and " +
+          "livy server log";
       throw new InterpreterException(msg, e);
     }
   }
@@ -187,17 +191,14 @@ public abstract class BaseLivyInterpreter extends Interpreter {
         sessionInfo.appId = extractAppId();
       }
 
-      if (sessionInfo.appInfo == null
-          || StringUtils.isEmpty(sessionInfo.appInfo.get("sparkUiUrl"))) {
+      if (sessionInfo.appInfo == null ||
+          StringUtils.isEmpty(sessionInfo.appInfo.get("sparkUiUrl"))) {
         sessionInfo.webUIAddress = extractWebUIAddress();
       } else {
         sessionInfo.webUIAddress = sessionInfo.appInfo.get("sparkUiUrl");
       }
-      LOGGER.info(
-          "Create livy session successfully with sessionId: {}, appId: {}, webUI: {}",
-          sessionInfo.id,
-          sessionInfo.appId,
-          sessionInfo.webUIAddress);
+      LOGGER.info("Create livy session successfully with sessionId: {}, appId: {}, webUI: {}",
+          sessionInfo.id, sessionInfo.appId, sessionInfo.webUIAddress);
     } else {
       LOGGER.info("Create livy session successfully with sessionId: {}", this.sessionInfo.id);
     }
@@ -234,20 +235,20 @@ public abstract class BaseLivyInterpreter extends Interpreter {
       return interpret(st, null, context.getParagraphId(), this.displayAppInfo, true, true);
     } catch (LivyException e) {
       LOGGER.error("Fail to interpret:" + st, e);
-      return new InterpreterResult(
-          InterpreterResult.Code.ERROR, InterpreterUtils.getMostRelevantMessage(e));
+      return new InterpreterResult(InterpreterResult.Code.ERROR,
+          InterpreterUtils.getMostRelevantMessage(e));
     }
   }
 
   @Override
-  public List<InterpreterCompletion> completion(
-      String buf, int cursor, InterpreterContext interpreterContext) {
+  public List<InterpreterCompletion> completion(String buf, int cursor,
+      InterpreterContext interpreterContext) {
     List<InterpreterCompletion> candidates = Collections.emptyList();
     try {
       candidates = callCompletion(new CompletionRequest(buf, getSessionKind(), cursor));
     } catch (SessionNotFoundException e) {
-      LOGGER.warn(
-          "Livy session {} is expired. Will return empty list of candidates.", getSessionInfo().id);
+      LOGGER.warn("Livy session {} is expired. Will return empty list of candidates.",
+          getSessionInfo().id);
     } catch (LivyException le) {
       logger.error("Failed to call code completions. Will return empty list of candidates", le);
     }
@@ -257,10 +258,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
   private List<InterpreterCompletion> callCompletion(CompletionRequest req) throws LivyException {
     List<InterpreterCompletion> candidates = new ArrayList<>();
     try {
-      CompletionResponse resp =
-          CompletionResponse.fromJson(
-              callRestAPI(
-                  "/sessions/" + getSessionInfo().id + "/completion", "POST", req.toJson()));
+      CompletionResponse resp = CompletionResponse.fromJson(
+          callRestAPI("/sessions/" + getSessionInfo().id + "/completion", "POST", req.toJson()));
       for (String candidate : resp.candidates) {
         candidates.add(new InterpreterCompletion(candidate, candidate, StringUtils.EMPTY));
       }
@@ -299,51 +298,37 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     return 0;
   }
 
-  private SessionInfo createSession(String user, String kind) throws LivyException {
+  private SessionInfo createSession(String user, String kind)
+      throws LivyException {
     try {
       Map<String, String> conf = new HashMap<>();
       for (Map.Entry<Object, Object> entry : getProperties().entrySet()) {
-        if (entry.getKey().toString().startsWith("livy.spark.")
-            && !entry.getValue().toString().isEmpty()) {
+        if (entry.getKey().toString().startsWith("livy.spark.") &&
+            !entry.getValue().toString().isEmpty()) {
           conf.put(entry.getKey().toString().substring(5), entry.getValue().toString());
         }
       }
 
-      CreateSessionRequest request =
-          new CreateSessionRequest(
-              kind, user == null || user.equals("anonymous") ? null : user, conf);
-      SessionInfo sessionInfo =
-          SessionInfo.fromJson(callRestAPI("/sessions", "POST", request.toJson()));
+      CreateSessionRequest request = new CreateSessionRequest(kind,
+          user == null || user.equals("anonymous") ? null : user, conf);
+      SessionInfo sessionInfo = SessionInfo.fromJson(
+          callRestAPI("/sessions", "POST", request.toJson()));
       long start = System.currentTimeMillis();
       // pull the session status until it is idle or timeout
       while (!sessionInfo.isReady()) {
         if ((System.currentTimeMillis() - start) / 1000 > sessionCreationTimeout) {
-          String msg =
-              "The creation of session "
-                  + sessionInfo.id
-                  + " is timeout within "
-                  + sessionCreationTimeout
-                  + " seconds, appId: "
-                  + sessionInfo.appId
-                  + ", log:\n"
-                  + StringUtils.join(getSessionLog(sessionInfo.id).log, "\n");
+          String msg = "The creation of session " + sessionInfo.id + " is timeout within "
+              + sessionCreationTimeout + " seconds, appId: " + sessionInfo.appId
+              + ", log:\n" + StringUtils.join(getSessionLog(sessionInfo.id).log, "\n");
           throw new LivyException(msg);
         }
         Thread.sleep(pullStatusInterval);
         sessionInfo = getSessionInfo(sessionInfo.id);
-        LOGGER.info(
-            "Session {} is in state {}, appId {}",
-            sessionInfo.id,
-            sessionInfo.state,
+        LOGGER.info("Session {} is in state {}, appId {}", sessionInfo.id, sessionInfo.state,
             sessionInfo.appId);
         if (sessionInfo.isFinished()) {
-          String msg =
-              "Session "
-                  + sessionInfo.id
-                  + " is finished, appId: "
-                  + sessionInfo.appId
-                  + ", log:\n"
-                  + StringUtils.join(getSessionLog(sessionInfo.id).log, "\n");
+          String msg = "Session " + sessionInfo.id + " is finished, appId: " + sessionInfo.appId
+              + ", log:\n" + StringUtils.join(getSessionLog(sessionInfo.id).log, "\n");
           throw new LivyException(msg);
         }
       }
@@ -359,34 +344,25 @@ public abstract class BaseLivyInterpreter extends Interpreter {
   }
 
   private SessionLog getSessionLog(int sessionId) throws LivyException {
-    return SessionLog.fromJson(
-        callRestAPI("/sessions/" + sessionId + "/log?size=" + maxLogLines, "GET"));
+    return SessionLog.fromJson(callRestAPI("/sessions/" + sessionId + "/log?size=" + maxLogLines,
+        "GET"));
   }
 
-  public InterpreterResult interpret(
-      String code,
-      String paragraphId,
-      boolean displayAppInfo,
-      boolean appendSessionExpired,
-      boolean appendSessionDead)
-      throws LivyException {
-    return interpret(
-        code,
-        sharedInterpreter.isSupported() ? getSessionKind() : null,
-        paragraphId,
-        displayAppInfo,
-        appendSessionExpired,
-        appendSessionDead);
-  }
-
-  public InterpreterResult interpret(
-      String code,
-      String codeType,
-      String paragraphId,
-      boolean displayAppInfo,
-      boolean appendSessionExpired,
-      boolean appendSessionDead)
-      throws LivyException {
+  public InterpreterResult interpret(String code,
+                                     String paragraphId,
+                                     boolean displayAppInfo,
+                                     boolean appendSessionExpired,
+                                     boolean appendSessionDead) throws LivyException {
+    return interpret(code, sharedInterpreter.isSupported() ? getSessionKind() : null,
+        paragraphId, displayAppInfo, appendSessionExpired, appendSessionDead);
+  }
+
+  public InterpreterResult interpret(String code,
+                                     String codeType,
+                                     String paragraphId,
+                                     boolean displayAppInfo,
+                                     boolean appendSessionExpired,
+                                     boolean appendSessionDead) throws LivyException {
     StatementInfo stmtInfo = null;
     boolean sessionExpired = false;
     boolean sessionDead = false;
@@ -417,9 +393,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
           }
           stmtInfo = executeStatement(new ExecuteRequest(code, codeType));
         } else {
-          throw new LivyException(
-              "%html <font color=\"red\">Livy session is dead somehow, "
-                  + "please check log to see why it is dead, and then restart livy interpreter</font>");
+          throw new LivyException("%html <font color=\"red\">Livy session is dead somehow, " +
+              "please check log to see why it is dead, and then restart livy interpreter</font>");
         }
       }
 
@@ -441,8 +416,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
         }
       }
       if (appendSessionExpired || appendSessionDead) {
-        return appendSessionExpireDead(
-            getResultFromStatementInfo(stmtInfo, displayAppInfo), sessionExpired, sessionDead);
+        return appendSessionExpireDead(getResultFromStatementInfo(stmtInfo, displayAppInfo),
+            sessionExpired, sessionDead);
       } else {
         return getResultFromStatementInfo(stmtInfo, displayAppInfo);
       }
@@ -485,20 +460,20 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     }
   }
 
-  private InterpreterResult appendSessionExpireDead(
-      InterpreterResult result, boolean sessionExpired, boolean sessionDead) {
+  private InterpreterResult appendSessionExpireDead(InterpreterResult result,
+                                                    boolean sessionExpired,
+                                                    boolean sessionDead) {
     InterpreterResult result2 = new InterpreterResult(result.code());
     if (sessionExpired) {
-      result2.add(
-          InterpreterResult.Type.HTML,
-          "<font color=\"red\">Previous livy session is expired, new livy session is created. "
-              + "Paragraphs that depend on this paragraph need to be re-executed!</font>");
+      result2.add(InterpreterResult.Type.HTML,
+          "<font color=\"red\">Previous livy session is expired, new livy session is created. " +
+              "Paragraphs that depend on this paragraph need to be re-executed!</font>");
+
     }
     if (sessionDead) {
-      result2.add(
-          InterpreterResult.Type.HTML,
-          "<font color=\"red\">Previous livy session is dead, new livy session is created. "
-              + "Paragraphs that depend on this paragraph need to be re-executed!</font>");
+      result2.add(InterpreterResult.Type.HTML,
+          "<font color=\"red\">Previous livy session is dead, new livy session is created. " +
+              "Paragraphs that depend on this paragraph need to be re-executed!</font>");
     }
 
     for (InterpreterResultMessage message : result.message()) {
@@ -507,8 +482,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     return result2;
   }
 
-  private InterpreterResult getResultFromStatementInfo(
-      StatementInfo stmtInfo, boolean displayAppInfo) {
+  private InterpreterResult getResultFromStatementInfo(StatementInfo stmtInfo,
+                                                       boolean displayAppInfo) {
     if (stmtInfo.output != null && stmtInfo.output.isError()) {
       InterpreterResult result = new InterpreterResult(InterpreterResult.Code.ERROR);
       StringBuilder sb = new StringBuilder();
@@ -530,7 +505,7 @@ public abstract class BaseLivyInterpreter extends Interpreter {
       // This case should never happen, just in case
       return new InterpreterResult(InterpreterResult.Code.ERROR, "Empty output");
     } else {
-      // TODO(zjffdu) support other types of data (like json, image and etc)
+      //TODO(zjffdu) support other types of data (like json, image and etc)
       String result = stmtInfo.output.data.plainText;
 
       // check table magic result first
@@ -551,13 +526,11 @@ public abstract class BaseLivyInterpreter extends Interpreter {
           outputBuilder.append(StringUtils.join(row, "\t"));
           outputBuilder.append("\n");
         }
-        return new InterpreterResult(
-            InterpreterResult.Code.SUCCESS, InterpreterResult.Type.TABLE, outputBuilder.toString());
+        return new InterpreterResult(InterpreterResult.Code.SUCCESS,
+            InterpreterResult.Type.TABLE, outputBuilder.toString());
       } else if (stmtInfo.output.data.imagePng != null) {
-        return new InterpreterResult(
-            InterpreterResult.Code.SUCCESS,
-            InterpreterResult.Type.IMG,
-            (String) stmtInfo.output.data.imagePng);
+        return new InterpreterResult(InterpreterResult.Code.SUCCESS,
+            InterpreterResult.Type.IMG, (String) stmtInfo.output.data.imagePng);
       } else if (result != null) {
         result = result.trim();
         if (result.startsWith("<link")
@@ -571,15 +544,9 @@ public abstract class BaseLivyInterpreter extends Interpreter {
       if (displayAppInfo) {
         InterpreterResult interpreterResult = new InterpreterResult(InterpreterResult.Code.SUCCESS);
         interpreterResult.add(result);
-        String appInfoHtml =
-            "<hr/>Spark Application Id: "
-                + sessionInfo.appId
-                + "<br/>"
-                + "Spark WebUI: <a href=\""
-                + sessionInfo.webUIAddress
-                + "\">"
-                + sessionInfo.webUIAddress
-                + "</a>";
+        String appInfoHtml = "<hr/>Spark Application Id: " + sessionInfo.appId + "<br/>"
+            + "Spark WebUI: <a href=\"" + sessionInfo.webUIAddress + "\">"
+            + sessionInfo.webUIAddress + "</a>";
         interpreterResult.add(InterpreterResult.Type.HTML, appInfoHtml);
         return interpreterResult;
       } else {
@@ -588,13 +555,14 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     }
   }
 
-  private StatementInfo executeStatement(ExecuteRequest executeRequest) throws LivyException {
-    return StatementInfo.fromJson(
-        callRestAPI(
-            "/sessions/" + sessionInfo.id + "/statements", "POST", executeRequest.toJson()));
+  private StatementInfo executeStatement(ExecuteRequest executeRequest)
+      throws LivyException {
+    return StatementInfo.fromJson(callRestAPI("/sessions/" + sessionInfo.id + "/statements", "POST",
+        executeRequest.toJson()));
   }
 
-  private StatementInfo getStatementInfo(int statementId) throws LivyException {
+  private StatementInfo getStatementInfo(int statementId)
+      throws LivyException {
     return StatementInfo.fromJson(
         callRestAPI("/sessions/" + sessionInfo.id + "/statements/" + statementId, "GET"));
   }
@@ -603,11 +571,12 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     callRestAPI("/sessions/" + sessionInfo.id + "/statements/" + statementId + "/cancel", "POST");
   }
 
+
   private RestTemplate createRestTemplate() {
     String keytabLocation = getProperty("zeppelin.livy.keytab");
     String principal = getProperty("zeppelin.livy.principal");
-    boolean isSpnegoEnabled =
-        StringUtils.isNotEmpty(keytabLocation) && StringUtils.isNotEmpty(principal);
+    boolean isSpnegoEnabled = StringUtils.isNotEmpty(keytabLocation) &&
+        StringUtils.isNotEmpty(principal);
 
     HttpClient httpClient = null;
     if (livyURL.startsWith("https:")) {
@@ -617,37 +586,37 @@ public abstract class BaseLivyInterpreter extends Interpreter {
         throw new RuntimeException("No zeppelin.livy.ssl.trustStore specified for livy ssl");
       }
       if (StringUtils.isBlank(password)) {
-        throw new RuntimeException(
-            "No zeppelin.livy.ssl.trustStorePassword specified " + "for livy ssl");
+        throw new RuntimeException("No zeppelin.livy.ssl.trustStorePassword specified " +
+            "for livy ssl");
       }
       FileInputStream inputStream = null;
       try {
         inputStream = new FileInputStream(keystoreFile);
         KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
         trustStore.load(new FileInputStream(keystoreFile), password.toCharArray());
-        SSLContext sslContext = SSLContexts.custom().loadTrustMaterial(trustStore).build();
+        SSLContext sslContext = SSLContexts.custom()
+            .loadTrustMaterial(trustStore)
+            .build();
         SSLConnectionSocketFactory csf = new SSLConnectionSocketFactory(sslContext);
         HttpClientBuilder httpClientBuilder = HttpClients.custom().setSSLSocketFactory(csf);
-        RequestConfig reqConfig =
-            new RequestConfig() {
-              @Override
-              public boolean isAuthenticationEnabled() {
-                return true;
-              }
-            };
+        RequestConfig reqConfig = new RequestConfig() {
+          @Override
+          public boolean isAuthenticationEnabled() {
+            return true;
+          }
+        };
         httpClientBuilder.setDefaultRequestConfig(reqConfig);
-        Credentials credentials =
-            new Credentials() {
-              @Override
-              public String getPassword() {
-                return null;
-              }
-
-              @Override
-              public Principal getUserPrincipal() {
-                return null;
-              }
-            };
+        Credentials credentials = new Credentials() {
+          @Override
+          public String getPassword() {
+            return null;
+          }
+
+          @Override
+          public Principal getUserPrincipal() {
+            return null;
+          }
+        };
         CredentialsProvider credsProvider = new BasicCredentialsProvider();
         credsProvider.setCredentials(AuthScope.ANY, credentials);
         httpClientBuilder.setDefaultCredentialsProvider(credsProvider);
@@ -687,9 +656,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
         restTemplate = new RestTemplate(new HttpComponentsClientHttpRequestFactory(httpClient));
       }
     }
-    restTemplate
-        .getMessageConverters()
-        .add(0, new StringHttpMessageConverter(Charset.forName("UTF-8")));
+    restTemplate.getMessageConverters().add(0,
+            new StringHttpMessageConverter(Charset.forName("UTF-8")));
     return restTemplate;
   }
 
@@ -721,10 +689,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
       }
     } catch (HttpClientErrorException e) {
       response = new ResponseEntity(e.getResponseBodyAsString(), e.getStatusCode());
-      LOGGER.error(
-          String.format(
-              "Error with %s StatusCode: %s",
-              response.getStatusCode().value(), e.getResponseBodyAsString()));
+      LOGGER.error(String.format("Error with %s StatusCode: %s",
+          response.getStatusCode().value(), e.getResponseBodyAsString()));
     } catch (RestClientException e) {
       // Exception happens when kerberos is enabled.
       if (e.getCause() instanceof HttpClientErrorException) {
@@ -732,10 +698,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
         if (cause.getResponseBodyAsString().matches(SESSION_NOT_FOUND_PATTERN)) {
           throw new SessionNotFoundException(cause.getResponseBodyAsString());
         }
-        throw new LivyException(
-            cause.getResponseBodyAsString()
-                + "\n"
-                + ExceptionUtils.getFullStackTrace(ExceptionUtils.getRootCause(e)));
+        throw new LivyException(cause.getResponseBodyAsString() + "\n"
+            + ExceptionUtils.getFullStackTrace(ExceptionUtils.getRootCause(e)));
       }
       if (e instanceof HttpServerErrorException) {
         HttpServerErrorException errorException = (HttpServerErrorException) e;
@@ -750,27 +714,25 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     if (response == null) {
       throw new LivyException("No http response returned");
     }
-    LOGGER.debug(
-        "Get response, StatusCode: {}, responseBody: {}",
-        response.getStatusCode(),
+    LOGGER.debug("Get response, StatusCode: {}, responseBody: {}", response.getStatusCode(),
         response.getBody());
-    if (response.getStatusCode().value() == 200 || response.getStatusCode().value() == 201) {
+    if (response.getStatusCode().value() == 200
+        || response.getStatusCode().value() == 201) {
       return response.getBody();
     } else if (response.getStatusCode().value() == 404) {
       if (response.getBody().matches(SESSION_NOT_FOUND_PATTERN)) {
         throw new SessionNotFoundException(response.getBody());
       } else {
-        throw new APINotFoundException(
-            "No rest api found for " + targetURL + ", " + response.getStatusCode());
+        throw new APINotFoundException("No rest api found for " + targetURL +
+            ", " + response.getStatusCode());
       }
     } else {
       String responseString = response.getBody();
       if (responseString.contains("CreateInteractiveRequest[\\\"master\\\"]")) {
         return responseString;
       }
-      throw new LivyException(
-          String.format(
-              "Error with %s StatusCode: %s", response.getStatusCode().value(), responseString));
+      throw new LivyException(String.format("Error with %s StatusCode: %s",
+          response.getStatusCode().value(), responseString));
     }
   }
 
@@ -778,23 +740,21 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     try {
       callRestAPI("/sessions/" + sessionId, "DELETE");
     } catch (Exception e) {
-      LOGGER.error(
-          String.format("Error closing session for user with session ID: %s", sessionId), e);
+      LOGGER.error(String.format("Error closing session for user with session ID: %s",
+          sessionId), e);
     }
   }
 
   /*
-   * We create these POJO here to accommodate livy 0.3 which is not released yet. livy rest api has
-   * some changes from version to version. So we create these POJO in zeppelin side to accommodate
-   * incompatibility between versions. Later, when livy become more stable, we could just depend on
-   * livy client jar.
-   */
+  * We create these POJO here to accommodate livy 0.3 which is not released yet. livy rest api has
+  * some changes from version to version. So we create these POJO in zeppelin side to accommodate
+  * incompatibility between versions. Later, when livy become more stable, we could just depend on
+  * livy client jar.
+  */
   private static class CreateSessionRequest {
     public final String kind;
-
     @SerializedName("proxyUser")
     public final String user;
-
     public final Map<String, String> conf;
 
     CreateSessionRequest(String kind, String user, Map<String, String> conf) {
@@ -808,7 +768,9 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     }
   }
 
-  /** */
+  /**
+   *
+   */
   public static class SessionInfo {
 
     public final int id;
@@ -821,15 +783,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     public final Map<String, String> appInfo;
     public final List<String> log;
 
-    public SessionInfo(
-        int id,
-        String appId,
-        String owner,
-        String proxyUser,
-        String state,
-        String kind,
-        Map<String, String> appInfo,
-        List<String> log) {
+    public SessionInfo(int id, String appId, String owner, String proxyUser, String state,
+                       String kind, Map<String, String> appInfo, List<String> log) {
       this.id = id;
       this.appId = appId;
       this.owner = owner;
@@ -859,7 +814,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     public int size;
     public List<String> log;
 
-    SessionLog() {}
+    SessionLog() {
+    }
 
     public static SessionLog fromJson(String json) {
       return gson.fromJson(json, SessionLog.class);
@@ -886,7 +842,8 @@ public abstract class BaseLivyInterpreter extends Interpreter {
     public double progress;
     public StatementOutput output;
 
-    StatementInfo() {}
+    StatementInfo() {
+    }
 
     public static StatementInfo fromJson(String json) {
       String rightJson = "";
@@ -931,13 +888,10 @@ public abstract class BaseLivyInterpreter extends Interpreter {
       private static class Data {
         @SerializedName("text/plain")
         public String plainText;
-
         @SerializedName("image/png")
         public String imagePng;
-
         @SerializedName("application/json")
         public String applicationJson;
-
         @SerializedName("application/vnd.livy.table.v1+json")
         public TableMagic applicationLivyTableJson;
       }

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/LivyException.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/LivyException.java b/livy/src/main/java/org/apache/zeppelin/livy/LivyException.java
index 4039004..c14351f 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/LivyException.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/LivyException.java
@@ -19,9 +19,12 @@ package org.apache.zeppelin.livy;
 
 import org.apache.zeppelin.interpreter.InterpreterException;
 
-/** Livy api related exception. */
+/**
+ * Livy api related exception.
+ */
 public class LivyException extends InterpreterException {
-  public LivyException() {}
+  public LivyException() {
+  }
 
   public LivyException(String message) {
     super(message);
@@ -35,8 +38,8 @@ public class LivyException extends InterpreterException {
     super(cause);
   }
 
-  public LivyException(
-      String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
+  public LivyException(String message, Throwable cause, boolean enableSuppression,
+                       boolean writableStackTrace) {
     super(message, cause, enableSuppression, writableStackTrace);
   }
 }

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/LivyPySpark3Interpreter.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/LivyPySpark3Interpreter.java b/livy/src/main/java/org/apache/zeppelin/livy/LivyPySpark3Interpreter.java
index d074e32..174c2c0 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/LivyPySpark3Interpreter.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/LivyPySpark3Interpreter.java
@@ -19,7 +19,10 @@ package org.apache.zeppelin.livy;
 
 import java.util.Properties;
 
-/** Livy PySpark interpreter for Zeppelin. */
+
+/**
+ * Livy PySpark interpreter for Zeppelin.
+ */
 public class LivyPySpark3Interpreter extends LivyPySparkBaseInterpreter {
 
   public LivyPySpark3Interpreter(Properties property) {
@@ -30,4 +33,5 @@ public class LivyPySpark3Interpreter extends LivyPySparkBaseInterpreter {
   public String getSessionKind() {
     return "pyspark3";
   }
+
 }

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/LivyPySparkBaseInterpreter.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/LivyPySparkBaseInterpreter.java b/livy/src/main/java/org/apache/zeppelin/livy/LivyPySparkBaseInterpreter.java
index c5729d1..32399c6 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/LivyPySparkBaseInterpreter.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/LivyPySparkBaseInterpreter.java
@@ -19,7 +19,9 @@ package org.apache.zeppelin.livy;
 
 import java.util.Properties;
 
-/** Base class for PySpark Interpreter. */
+/**
+ * Base class for PySpark Interpreter.
+ */
 public abstract class LivyPySparkBaseInterpreter extends BaseLivyInterpreter {
 
   public LivyPySparkBaseInterpreter(Properties property) {
@@ -29,21 +31,22 @@ public abstract class LivyPySparkBaseInterpreter extends BaseLivyInterpreter {
   @Override
   protected String extractAppId() throws LivyException {
     return extractStatementResult(
-        interpret("sc.applicationId", null, false, false, false).message().get(0).getData());
+        interpret("sc.applicationId", null, false, false, false).message()
+            .get(0).getData());
   }
 
   @Override
   protected String extractWebUIAddress() throws LivyException {
     return extractStatementResult(
-        interpret("sc._jsc.sc().ui().get().appUIAddress()", null, false, false, false)
-            .message()
-            .get(0)
-            .getData());
+        interpret(
+            "sc._jsc.sc().ui().get().appUIAddress()", null, false, false, false)
+            .message().get(0).getData());
   }
 
   /**
-   * Extract the eval result of spark shell, e.g. extract application_1473129941656_0048 from
-   * following: u'application_1473129941656_0048'
+   * Extract the eval result of spark shell, e.g. extract application_1473129941656_0048
+   * from following:
+   * u'application_1473129941656_0048'
    *
    * @param result
    * @return
@@ -53,8 +56,8 @@ public abstract class LivyPySparkBaseInterpreter extends BaseLivyInterpreter {
     if ((pos = result.indexOf("'")) >= 0) {
       return result.substring(pos + 1, result.length() - 1).trim();
     } else {
-      throw new RuntimeException(
-          "No result can be extracted from '" + result + "', " + "something must be wrong");
+      throw new RuntimeException("No result can be extracted from '" + result + "', " +
+          "something must be wrong");
     }
   }
 }

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/LivyPySparkInterpreter.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/LivyPySparkInterpreter.java b/livy/src/main/java/org/apache/zeppelin/livy/LivyPySparkInterpreter.java
index 9b15274..d664bbe 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/LivyPySparkInterpreter.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/LivyPySparkInterpreter.java
@@ -19,7 +19,10 @@ package org.apache.zeppelin.livy;
 
 import java.util.Properties;
 
-/** Livy PySpark interpreter for Zeppelin. */
+
+/**
+ * Livy PySpark interpreter for Zeppelin.
+ */
 public class LivyPySparkInterpreter extends LivyPySparkBaseInterpreter {
 
   public LivyPySparkInterpreter(Properties property) {
@@ -30,4 +33,6 @@ public class LivyPySparkInterpreter extends LivyPySparkBaseInterpreter {
   public String getSessionKind() {
     return "pyspark";
   }
+
+
 }

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/LivySharedInterpreter.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/LivySharedInterpreter.java b/livy/src/main/java/org/apache/zeppelin/livy/LivySharedInterpreter.java
index df0fd07..c912dc9 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/LivySharedInterpreter.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/LivySharedInterpreter.java
@@ -17,16 +17,20 @@
 
 package org.apache.zeppelin.livy;
 
-import java.util.Properties;
 import org.apache.commons.lang.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Properties;
+
 import org.apache.zeppelin.interpreter.InterpreterContext;
 import org.apache.zeppelin.interpreter.InterpreterException;
 import org.apache.zeppelin.interpreter.InterpreterResult;
 import org.apache.zeppelin.interpreter.InterpreterUtils;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
-/** Livy Interpreter for shared kind which share SparkContext across spark/pyspark/r. */
+/**
+ * Livy Interpreter for shared kind which share SparkContext across spark/pyspark/r.
+ */
 public class LivySharedInterpreter extends BaseLivyInterpreter {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(LivySharedInterpreter.class);
@@ -59,8 +63,8 @@ public class LivySharedInterpreter extends BaseLivyInterpreter {
         isSupported = false;
       }
     } catch (LivyException e) {
-      String msg =
-          "Fail to create session, please check livy interpreter log and " + "livy server log";
+      String msg = "Fail to create session, please check livy interpreter log and " +
+          "livy server log";
       throw new InterpreterException(msg, e);
     }
   }
@@ -78,8 +82,8 @@ public class LivySharedInterpreter extends BaseLivyInterpreter {
       return interpret(st, codeType, context.getParagraphId(), this.displayAppInfo, true, true);
     } catch (LivyException e) {
       LOGGER.error("Fail to interpret:" + st, e);
-      return new InterpreterResult(
-          InterpreterResult.Code.ERROR, InterpreterUtils.getMostRelevantMessage(e));
+      return new InterpreterResult(InterpreterResult.Code.ERROR,
+          InterpreterUtils.getMostRelevantMessage(e));
     }
   }
 

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/LivySparkInterpreter.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/LivySparkInterpreter.java b/livy/src/main/java/org/apache/zeppelin/livy/LivySparkInterpreter.java
index e7b3570..ad62e9b 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/LivySparkInterpreter.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/LivySparkInterpreter.java
@@ -19,7 +19,9 @@ package org.apache.zeppelin.livy;
 
 import java.util.Properties;
 
-/** Livy Spark interpreter for Zeppelin. */
+/**
+ * Livy Spark interpreter for Zeppelin.
+ */
 public class LivySparkInterpreter extends BaseLivyInterpreter {
 
   public LivySparkInterpreter(Properties property) {
@@ -34,7 +36,8 @@ public class LivySparkInterpreter extends BaseLivyInterpreter {
   @Override
   protected String extractAppId() throws LivyException {
     return extractStatementResult(
-        interpret("sc.applicationId", null, false, false, false).message().get(0).getData());
+        interpret("sc.applicationId", null, false, false, false).message()
+            .get(0).getData());
   }
 
   @Override
@@ -42,25 +45,17 @@ public class LivySparkInterpreter extends BaseLivyInterpreter {
     interpret(
         "val webui=sc.getClass.getMethod(\"ui\").invoke(sc).asInstanceOf[Some[_]].get",
         null,
-        null,
-        false,
-        false,
-        false);
+        null, false, false, false);
     return extractStatementResult(
         interpret(
-                "webui.getClass.getMethod(\"appUIAddress\").invoke(webui)",
-                null,
-                false,
-                false,
-                false)
-            .message()
-            .get(0)
-            .getData());
+            "webui.getClass.getMethod(\"appUIAddress\").invoke(webui)", null, false, false, false)
+            .message().get(0).getData());
   }
 
   /**
-   * Extract the eval result of spark shell, e.g. extract application_1473129941656_0048 from
-   * following: res0: String = application_1473129941656_0048
+   * Extract the eval result of spark shell, e.g. extract application_1473129941656_0048
+   * from following:
+   * res0: String = application_1473129941656_0048
    *
    * @param result
    * @return
@@ -70,8 +65,8 @@ public class LivySparkInterpreter extends BaseLivyInterpreter {
     if ((pos = result.indexOf("=")) >= 0) {
       return result.substring(pos + 1).trim();
     } else {
-      throw new RuntimeException(
-          "No result can be extracted from '" + result + "', " + "something must be wrong");
+      throw new RuntimeException("No result can be extracted from '" + result + "', " +
+          "something must be wrong");
     }
   }
 }

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/LivySparkRInterpreter.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/LivySparkRInterpreter.java b/livy/src/main/java/org/apache/zeppelin/livy/LivySparkRInterpreter.java
index 6aab4f0..c270437 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/LivySparkRInterpreter.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/LivySparkRInterpreter.java
@@ -19,7 +19,10 @@ package org.apache.zeppelin.livy;
 
 import java.util.Properties;
 
-/** Livy PySpark interpreter for Zeppelin. */
+
+/**
+ * Livy PySpark interpreter for Zeppelin.
+ */
 public class LivySparkRInterpreter extends BaseLivyInterpreter {
 
   public LivySparkRInterpreter(Properties property) {
@@ -33,13 +36,13 @@ public class LivySparkRInterpreter extends BaseLivyInterpreter {
 
   @Override
   protected String extractAppId() throws LivyException {
-    // TODO(zjffdu) depends on SparkR
+    //TODO(zjffdu) depends on SparkR
     return null;
   }
 
   @Override
   protected String extractWebUIAddress() throws LivyException {
-    // TODO(zjffdu) depends on SparkR
+    //TODO(zjffdu) depends on SparkR
     return null;
   }
 }

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/LivySparkSQLInterpreter.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/LivySparkSQLInterpreter.java b/livy/src/main/java/org/apache/zeppelin/livy/LivySparkSQLInterpreter.java
index 12c641a..b2e18f3 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/LivySparkSQLInterpreter.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/LivySparkSQLInterpreter.java
@@ -17,11 +17,6 @@
 
 package org.apache.zeppelin.livy;
 
-import static org.apache.commons.lang.StringEscapeUtils.escapeJavaScript;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Properties;
 import org.apache.commons.lang.StringUtils;
 import org.apache.zeppelin.interpreter.InterpreterContext;
 import org.apache.zeppelin.interpreter.InterpreterException;
@@ -33,7 +28,15 @@ import org.apache.zeppelin.interpreter.ResultMessages;
 import org.apache.zeppelin.scheduler.Scheduler;
 import org.apache.zeppelin.scheduler.SchedulerFactory;
 
-/** Livy SparkSQL Interpreter for Zeppelin. */
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Properties;
+
+import static org.apache.commons.lang.StringEscapeUtils.escapeJavaScript;
+
+/**
+ * Livy SparkSQL Interpreter for Zeppelin.
+ */
 public class LivySparkSQLInterpreter extends BaseLivyInterpreter {
   public static final String ZEPPELIN_LIVY_SPARK_SQL_FIELD_TRUNCATE =
       "zeppelin.livy.spark.sql.field.truncate";
@@ -68,13 +71,13 @@ public class LivySparkSQLInterpreter extends BaseLivyInterpreter {
     // As we don't know whether livyserver use spark2 or spark1, so we will detect SparkSession
     // to judge whether it is using spark2.
     try {
-      InterpreterContext context =
-          InterpreterContext.builder().setInterpreterOut(new InterpreterOutput(null)).build();
+      InterpreterContext context = InterpreterContext.builder()
+          .setInterpreterOut(new InterpreterOutput(null))
+          .build();
       InterpreterResult result = sparkInterpreter.interpret("spark", context);
-      if (result.code() == InterpreterResult.Code.SUCCESS
-          && result.message().get(0).getData().contains("org.apache.spark.sql.SparkSession")) {
-        LOGGER.info(
-            "SparkSession is detected so we are using spark 2.x for session {}",
+      if (result.code() == InterpreterResult.Code.SUCCESS &&
+          result.message().get(0).getData().contains("org.apache.spark.sql.SparkSession")) {
+        LOGGER.info("SparkSession is detected so we are using spark 2.x for session {}",
             sparkInterpreter.getSessionInfo().id);
         isSpark2 = true;
       } else {
@@ -86,14 +89,12 @@ public class LivySparkSQLInterpreter extends BaseLivyInterpreter {
           // create SqlContext if it is not available, as in livy 0.2 sqlContext
           // is not available.
           LOGGER.info("sqlContext is not detected, try to create SQLContext by ourselves");
-          result =
-              sparkInterpreter.interpret(
-                  "val sqlContext = new org.apache.spark.sql.SQLContext(sc)\n"
-                      + "import sqlContext.implicits._",
-                  context);
+          result = sparkInterpreter.interpret(
+              "val sqlContext = new org.apache.spark.sql.SQLContext(sc)\n"
+                  + "import sqlContext.implicits._", context);
           if (result.code() == InterpreterResult.Code.ERROR) {
-            throw new LivyException(
-                "Fail to create SQLContext," + result.message().get(0).getData());
+            throw new LivyException("Fail to create SQLContext," +
+                result.message().get(0).getData());
           }
         }
       }
@@ -112,10 +113,11 @@ public class LivySparkSQLInterpreter extends BaseLivyInterpreter {
       // use triple quote so that we don't need to do string escape.
       String sqlQuery = null;
       if (isSpark2) {
-        sqlQuery = "spark.sql(\"\"\"" + line + "\"\"\").show(" + maxResult + ", " + truncate + ")";
+        sqlQuery = "spark.sql(\"\"\"" + line + "\"\"\").show(" + maxResult + ", " +
+            truncate + ")";
       } else {
-        sqlQuery =
-            "sqlContext.sql(\"\"\"" + line + "\"\"\").show(" + maxResult + ", " + truncate + ")";
+        sqlQuery = "sqlContext.sql(\"\"\"" + line + "\"\"\").show(" + maxResult + ", " +
+            truncate + ")";
       }
       InterpreterResult result = sparkInterpreter.interpret(sqlQuery, context);
       if (result.code() == InterpreterResult.Code.SUCCESS) {
@@ -128,9 +130,8 @@ public class LivySparkSQLInterpreter extends BaseLivyInterpreter {
             List<String> rows = parseSQLOutput(message.getData());
             result2.add(InterpreterResult.Type.TABLE, StringUtils.join(rows, "\n"));
             if (rows.size() >= (maxResult + 1)) {
-              result2.add(
-                  ResultMessages.getExceedsLimitRowsMessage(
-                      maxResult, ZEPPELIN_LIVY_SPARK_SQL_MAX_RESULT));
+              result2.add(ResultMessages.getExceedsLimitRowsMessage(maxResult,
+                  ZEPPELIN_LIVY_SPARK_SQL_MAX_RESULT));
             }
           } else {
             result2.add(message.getType(), message.getData());
@@ -142,8 +143,8 @@ public class LivySparkSQLInterpreter extends BaseLivyInterpreter {
       }
     } catch (Exception e) {
       LOGGER.error("Exception in LivySparkSQLInterpreter while interpret ", e);
-      return new InterpreterResult(
-          InterpreterResult.Code.ERROR, InterpreterUtils.getMostRelevantMessage(e));
+      return new InterpreterResult(InterpreterResult.Code.ERROR,
+          InterpreterUtils.getMostRelevantMessage(e));
     }
   }
 
@@ -201,7 +202,9 @@ public class LivySparkSQLInterpreter extends BaseLivyInterpreter {
     return rows;
   }
 
-  /** Represent the start and end index of each cell. */
+  /**
+   * Represent the start and end index of each cell.
+   */
   private static class Pair {
     private int start;
     private int end;
@@ -220,9 +223,8 @@ public class LivySparkSQLInterpreter extends BaseLivyInterpreter {
   public Scheduler getScheduler() {
     if (concurrentSQL()) {
       int maxConcurrency = 10;
-      return SchedulerFactory.singleton()
-          .createOrGetParallelScheduler(
-              LivySparkInterpreter.class.getName() + this.hashCode(), maxConcurrency);
+      return SchedulerFactory.singleton().createOrGetParallelScheduler(
+          LivySparkInterpreter.class.getName() + this.hashCode(), maxConcurrency);
     } else {
       if (sparkInterpreter != null) {
         return sparkInterpreter.getScheduler();

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/LivyVersion.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/LivyVersion.java b/livy/src/main/java/org/apache/zeppelin/livy/LivyVersion.java
index 1d56e83..55ebd57 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/LivyVersion.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/LivyVersion.java
@@ -20,7 +20,9 @@ package org.apache.zeppelin.livy;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-/** Provide reading comparing capability of livy version. */
+/**
+ * Provide reading comparing capability of livy version.
+ */
 public class LivyVersion {
   private static final Logger logger = LoggerFactory.getLogger(LivyVersion.class);
 
@@ -50,8 +52,8 @@ public class LivyVersion {
       // version is always 5 digits. (e.g. 2.0.0 -> 20000, 1.6.2 -> 10602)
       version = Integer.parseInt(String.format("%d%02d%02d", major, minor, patch));
     } catch (Exception e) {
-      logger.error(
-          "Can not recognize Livy version " + versionString + ". Assume it's a future release", e);
+      logger.error("Can not recognize Livy version " + versionString +
+          ". Assume it's a future release", e);
 
       // assume it is future release
       version = 99999;

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/SessionDeadException.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/SessionDeadException.java b/livy/src/main/java/org/apache/zeppelin/livy/SessionDeadException.java
index dfbb56e..5811790 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/SessionDeadException.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/SessionDeadException.java
@@ -17,4 +17,6 @@
 
 package org.apache.zeppelin.livy;
 
-public class SessionDeadException extends LivyException {}
+public class SessionDeadException extends LivyException {
+
+}

http://git-wip-us.apache.org/repos/asf/zeppelin/blob/0d746fa2/livy/src/main/java/org/apache/zeppelin/livy/SessionNotFoundException.java
----------------------------------------------------------------------
diff --git a/livy/src/main/java/org/apache/zeppelin/livy/SessionNotFoundException.java b/livy/src/main/java/org/apache/zeppelin/livy/SessionNotFoundException.java
index 3f56116..4547057 100644
--- a/livy/src/main/java/org/apache/zeppelin/livy/SessionNotFoundException.java
+++ b/livy/src/main/java/org/apache/zeppelin/livy/SessionNotFoundException.java
@@ -17,7 +17,9 @@
 
 package org.apache.zeppelin.livy;
 
-/** */
+/**
+ *
+ */
 public class SessionNotFoundException extends LivyException {
 
   public SessionNotFoundException(String message) {