diff --git a/.travis.yml b/.travis.yml
index 6c5eee3..d38cf4f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -33,17 +33,13 @@
       # Spark 2.2+ will only be verified using JDK8
       # Thriftserver requires JDK8
     - env: MVN_FLAG='-Pthriftserver -Pspark-2.2-it -DskipTests'
-      jdk: oraclejdk8
     - env: MVN_FLAG='-Pthriftserver -Pspark-2.2 -DskipITs'
-      jdk: oraclejdk8
     - env: MVN_FLAG='-Pthriftserver -Pspark-2.3-it -DskipTests'
-      jdk: oraclejdk8
     - env: MVN_FLAG='-Pthriftserver -Pspark-2.3 -DskipITs'
-      jdk: oraclejdk8
 
 
 jdk:
-  - openjdk7
+  - oraclejdk8
 
 addons:
   apt:
diff --git a/README.md b/README.md
index 2dc33c2..ff6ae16 100644
--- a/README.md
+++ b/README.md
@@ -28,19 +28,19 @@
 
 Debian/Ubuntu:
   * mvn (from ``maven`` package or maven3 tarball)
-  * openjdk-7-jdk (or Oracle Java7 jdk)
+  * openjdk-8-jdk (or Oracle JDK 8)
   * Python 2.6+
   * R 3.x
 
 Redhat/CentOS:
   * mvn (from ``maven`` package or maven3 tarball)
-  * java-1.7.0-openjdk (or Oracle Java7 jdk)
+  * java-1.8.0-openjdk (or Oracle JDK 8)
   * Python 2.6+
   * R 3.x
 
 MacOS:
   * Xcode command line tools
-  * Oracle's JDK 1.7+
+  * Oracle's JDK 1.8
   * Maven (Homebrew)
   * Python 2.6+
   * R 3.x
diff --git a/integration-test/src/main/scala/org/apache/livy/test/framework/MiniCluster.scala b/integration-test/src/main/scala/org/apache/livy/test/framework/MiniCluster.scala
index c4d4eb5..b58abe2 100644
--- a/integration-test/src/main/scala/org/apache/livy/test/framework/MiniCluster.scala
+++ b/integration-test/src/main/scala/org/apache/livy/test/framework/MiniCluster.scala
@@ -101,6 +101,10 @@
       config.localDirCount, config.logDirCount)
     yarnCluster.init(baseConfig)
 
+    // This allows applications run by YARN during the integration tests to find PIP modules
+    // installed in the user's home directory (instead of just the global ones).
+    baseConfig.set(YarnConfiguration.NM_USER_HOME_DIR, sys.env("HOME"))
+
     // Install a shutdown hook for stop the service and kill all running applications.
     Runtime.getRuntime().addShutdownHook(new Thread() {
       override def run(): Unit = yarnCluster.stop()
@@ -283,8 +287,7 @@
         sys.props("java.home") + "/bin/java",
         "-Dtest.appender=console",
         "-Djava.io.tmpdir=" + procTmp.getAbsolutePath(),
-        "-cp", childClasspath + File.pathSeparator + configDir.getAbsolutePath(),
-        "-XX:MaxPermSize=256m") ++
+        "-cp", childClasspath + File.pathSeparator + configDir.getAbsolutePath()) ++
       extraJavaArgs ++
       Seq(
         klass.getName().stripSuffix("$"),
diff --git a/integration-test/src/test/resources/test_python_api.py b/integration-test/src/test/resources/test_python_api.py
index 3749e69..d3023c0 100644
--- a/integration-test/src/test/resources/test_python_api.py
+++ b/integration-test/src/test/resources/test_python_api.py
@@ -217,7 +217,6 @@
 
 
 if __name__ == '__main__':
-    test_dir_path = os.getcwd() + "/src"
-    value = pytest.main(test_dir_path)
+    value = pytest.main([os.path.dirname(__file__)])
     if value != 0:
         raise Exception("One or more test cases have failed.")
diff --git a/integration-test/src/test/scala/org/apache/livy/test/JobApiIT.scala b/integration-test/src/test/scala/org/apache/livy/test/JobApiIT.scala
index 7c0e560..93b2524 100644
--- a/integration-test/src/test/scala/org/apache/livy/test/JobApiIT.scala
+++ b/integration-test/src/test/scala/org/apache/livy/test/JobApiIT.scala
@@ -249,7 +249,12 @@
     val uploadPyFilePath = createTempFilesForTest("upload_pyfile", ".py",
       uploadPyFileContent, false)
 
-    val builder = new ProcessBuilder(Seq("python", createPyTestsForPythonAPI().toString).asJava)
+    val tmpDir = new File(sys.props("java.io.tmpdir")).getAbsoluteFile()
+    val testDir = Files.createTempDirectory(tmpDir.toPath(), "python-tests-").toFile()
+    val testFile = createPyTestsForPythonAPI(testDir)
+
+    val builder = new ProcessBuilder(Seq("python", testFile.getAbsolutePath()).asJava)
+    builder.directory(testDir)
 
     val env = builder.environment()
     env.put("LIVY_END_POINT", livyEndpoint)
@@ -258,8 +263,8 @@
     env.put("UPLOAD_FILE_URL", uploadFilePath)
     env.put("UPLOAD_PYFILE_URL", uploadPyFilePath)
 
-    builder.redirectOutput(new File(sys.props("java.io.tmpdir") + "/pytest_results.log"))
     builder.redirectErrorStream(true)
+    builder.redirectOutput(new File(tmpDir, "pytest_results.log"))
 
     val process = builder.start()
 
@@ -268,11 +273,10 @@
     assert(process.exitValue() === 0)
   }
 
-  private def createPyTestsForPythonAPI(): File = {
-    var source: InputStream = null
+  private def createPyTestsForPythonAPI(testDir: File): File = {
+    val file = Files.createTempFile(testDir.toPath(), "test_python_api-", ".py").toFile()
+    val source = getClass().getClassLoader().getResourceAsStream("test_python_api.py")
     try {
-      source = getClass.getClassLoader.getResourceAsStream("test_python_api.py")
-      val file = Files.createTempFile("", "").toFile
       Files.copy(source, file.toPath, StandardCopyOption.REPLACE_EXISTING)
       file
     } finally {
diff --git a/pom.xml b/pom.xml
index e07f39d..b49c524 100644
--- a/pom.xml
+++ b/pom.xml
@@ -90,7 +90,7 @@
     <httpcore.version>4.4.4</httpcore.version>
     <jackson.version>2.9.5</jackson.version>
     <javax.servlet-api.version>3.1.0</javax.servlet-api.version>
-    <jetty.version>9.2.16.v20160414</jetty.version>
+    <jetty.version>9.3.8.v20160314</jetty.version>
     <json4s.version>3.2.10</json4s.version>
     <junit.version>4.11</junit.version>
     <libthrift.version>0.9.3</libthrift.version>
@@ -108,9 +108,7 @@
     <scala.version>${scala-2.11.version}</scala.version>
     <scalatest.version>2.2.4</scalatest.version>
     <scalatra.version>2.3.0</scalatra.version>
-    <java.version>1.7</java.version>
-    <minJavaVersion>1.7</minJavaVersion>
-    <maxJavaVersion>1.8</maxJavaVersion>
+    <java.version>1.8</java.version>
     <test.redirectToFile>true</test.redirectToFile>
     <execution.root>${user.dir}</execution.root>
     <spark.home>${execution.root}/dev/spark</spark.home>
@@ -580,26 +578,6 @@
       <plugins>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
-          <artifactId>maven-enforcer-plugin</artifactId>
-          <version>1.4.1</version>
-          <executions>
-            <execution>
-              <id>enforce-versions</id>
-              <goals>
-                <goal>enforce</goal>
-              </goals>
-              <configuration>
-                <rules>
-                  <requireJavaVersion>
-                    <version>1.7</version>
-                  </requireJavaVersion>
-                </rules>
-              </configuration>
-            </execution>
-          </executions>
-        </plugin>
-        <plugin>
-          <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-compiler-plugin</artifactId>
           <version>3.3</version>
         </plugin>
@@ -675,7 +653,6 @@
             <jvmArgs>
               <jvmArg>-Xms1024m</jvmArg>
               <jvmArg>-Xmx1024m</jvmArg>
-              <jvmArg>-XX:MaxPermSize=${MaxPermGen}</jvmArg>
               <jvmArg>-XX:ReservedCodeCacheSize=${CodeCacheSize}</jvmArg>
             </jvmArgs>
           </configuration>
@@ -714,7 +691,7 @@
             </systemProperties>
             <redirectTestOutputToFile>${test.redirectToFile}</redirectTestOutputToFile>
             <useFile>${test.redirectToFile}</useFile>
-            <argLine>${argLine} -Xmx2g -XX:MaxPermSize=512m</argLine>
+            <argLine>${argLine} -Xmx2g</argLine>
             <failIfNoTests>false</failIfNoTests>
           </configuration>
         </plugin>
@@ -743,7 +720,7 @@
             <reportsDirectory>${project.build.directory}/surefire-reports</reportsDirectory>
             <junitxml>.</junitxml>
             <filereports>WDF TestSuite.txt</filereports>
-            <argLine>${argLine} -Xmx2g -XX:MaxPermSize=512m</argLine>
+            <argLine>${argLine} -Xmx2g</argLine>
           </configuration>
           <executions>
             <execution>
@@ -818,12 +795,12 @@
         <inherited>false</inherited>
         <configuration>
           <rules>
+            <requireJavaVersion>
+              <version>${java.version}</version>
+            </requireJavaVersion>
             <requireMavenVersion>
               <version>[3.0.0,)</version>
             </requireMavenVersion>
-            <requireJavaVersion>
-              <version>[${minJavaVersion}.0,${maxJavaVersion}.1000}]</version>
-            </requireJavaVersion>
             <requireOS>
               <family>unix</family>
             </requireOS>
@@ -831,26 +808,12 @@
         </configuration>
         <executions>
           <execution>
-            <id>clean</id>
-            <goals>
-              <goal>enforce</goal>
-            </goals>
-            <phase>pre-clean</phase>
-          </execution>
-          <execution>
             <id>default</id>
             <goals>
               <goal>enforce</goal>
             </goals>
             <phase>validate</phase>
           </execution>
-          <execution>
-            <id>site</id>
-            <goals>
-              <goal>enforce</goal>
-            </goals>
-            <phase>pre-site</phase>
-          </execution>
         </executions>
       </plugin>
 
@@ -996,7 +959,7 @@
       <plugin>
         <groupId>org.jacoco</groupId>
         <artifactId>jacoco-maven-plugin</artifactId>
-        <version>0.7.7.201606060606</version>
+        <version>0.8.2</version>
         <executions>
           <execution>
             <goals>
@@ -1065,33 +1028,6 @@
       <modules>
         <module>thriftserver/server</module>
       </modules>
-      <properties>
-        <jetty.version>9.3.8.v20160314</jetty.version>
-      </properties>
-
-      <build>
-        <plugins>
-          <plugin>
-            <groupId>org.apache.maven.plugins</groupId>
-            <artifactId>maven-enforcer-plugin</artifactId>
-            <executions>
-              <execution>
-                <id>enforce-java</id>
-                <goals>
-                  <goal>enforce</goal>
-                </goals>
-                <configuration>
-                  <rules>
-                    <requireJavaVersion>
-                      <version>1.8</version>
-                    </requireJavaVersion>
-                  </rules>
-                </configuration>
-              </execution>
-            </executions>
-          </plugin>
-        </plugins>
-      </build>
     </profile>
 
     <!-- Spark version profiles -->
@@ -1184,7 +1120,6 @@
         <spark.scala-2.11.version>2.2.0</spark.scala-2.11.version>
         <spark.scala-2.10.version>2.2.0</spark.scala-2.10.version>
         <spark.version>${spark.scala-2.11.version}</spark.version>
-        <java.version>1.8</java.version>
         <py4j.version>0.10.4</py4j.version>
         <json4s.version>3.2.11</json4s.version>
       </properties>
@@ -1218,7 +1153,6 @@
         <spark.version>${spark.scala-2.11.version}</spark.version>
         <netty.spark-2.11.version>4.1.17.Final</netty.spark-2.11.version>
         <netty.spark-2.10.version>4.0.37.Final</netty.spark-2.10.version>
-        <java.version>1.8</java.version>
         <py4j.version>0.10.7</py4j.version>
         <json4s.version>3.2.11</json4s.version>
       </properties>
diff --git a/python-api/setup.cfg b/python-api/setup.cfg
index e2121f9..8a8799b 100644
--- a/python-api/setup.cfg
+++ b/python-api/setup.cfg
@@ -4,3 +4,4 @@
 [tool:pytest]
 addopts = --verbose
 python_files = src/test/python/*/*.py
+cache_dir = target/.pytest_cache
diff --git a/repl/src/main/scala/org/apache/livy/repl/PythonInterpreter.scala b/repl/src/main/scala/org/apache/livy/repl/PythonInterpreter.scala
index 97e746f..bab2bfa 100644
--- a/repl/src/main/scala/org/apache/livy/repl/PythonInterpreter.scala
+++ b/repl/src/main/scala/org/apache/livy/repl/PythonInterpreter.scala
@@ -201,9 +201,11 @@
           .newInstance(parts(0), gateway)
       } catch {
         case NonFatal(e) =>
-          classOf[PythonProxyHandler].getConstructor(classOf[String],
-            Class.forName("py4j.CallbackClient"), classOf[Gateway])
-            .newInstance(parts(0), gateway.getCallbackClient, gateway)
+          val cbClient = gateway.getClass().getMethod("getCallbackClient").invoke(gateway)
+          val cbClass = Class.forName("py4j.CallbackClient")
+          classOf[PythonProxyHandler]
+            .getConstructor(classOf[String], cbClass, classOf[Gateway])
+            .newInstance(parts(0), cbClient, gateway)
       }
 
       Proxy.newProxyInstance(Thread.currentThread.getContextClassLoader,