Added Java Interpreter Utils and tests for them.

beam/pom.xml

@@ -109,6 +109,12 @@
       </exclusions>
     </dependency>
 
+    <dependency>
+      <groupId>org.apache.zeppelin</groupId>
+      <artifactId>zeppelin-java</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+
     <dependency>
       <groupId>org.apache.zeppelin</groupId>
       <artifactId>zeppelin-scio_${scala.binary.version}</artifactId>
@@ -228,13 +234,6 @@
       <scope>provided</scope>
     </dependency>
 
-    <dependency>
-      <groupId>${project.groupId}</groupId>
-      <artifactId>zeppelin-java</artifactId>
-      <version>${project.version}</version>
-      <scope>provided</scope>
-    </dependency>
-
     <dependency>
       <groupId>org.apache.commons</groupId>
       <artifactId>commons-exec</artifactId>

java/README.md

@@ -15,7 +15,7 @@ mvn clean package -Pjava -DskipTests -Pscala-2.10
 
  * Upon starting an interpreter, an instance of `JavaCompiler` is created. 
 
- * When the user runs commands with beam, the `JavaParser` go through the code to get a class that contains the main method.
+ * When the user runs commands with java, the `JavaParser` go through the code to get a class that contains the main method.
  
  * Then it replaces the class name with random class name to avoid overriding while compilation. It creates new out & err stream to get the data in new stream instead of the console, to redirect output to zeppelin.
  

java/src/main/java/org/apache/zeppelin/java/JavaInterpreterUtils.java

@@ -0,0 +1,44 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.zeppelin.java;
+
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * Java interpreter utility methods
+ */
+public class JavaInterpreterUtils {
+
+  /**
+   * Convert a map to %table display system to leverage Zeppelin's built in visualization
+   * @param keyName Key column name
+   * @param valueName Value column name
+   * @param rows Map of keys and values
+   * @return Zeppelin %table
+   */
+  public static String displayTableFromSimpleMap(String keyName, String valueName, Map<?, ?> rows){
+    String table = "%table\n";
+    table += keyName + "\t" + valueName + "\n";
+    table += rows.entrySet().stream()
+            .map(e -> e.getKey() + "\t" + e.getValue())
+            .collect(Collectors.joining("\n"));
+    return table;
+  }
+
+}

java/src/test/org/apache/zeppelin/java/JavaInterpreterTest.java

@@ -65,6 +65,7 @@ public class JavaInterpreterTest {
     InterpreterResult res = java.interpret(writer.toString(), context);
 
     assertEquals(InterpreterResult.Code.SUCCESS, res.code());
+    assertEquals(InterpreterResult.Type.TEXT, res.message().get(0).getType());
   }
 
   @Test

java/src/test/org/apache/zeppelin/java/JavaInterpreterUtilsTest.java

@@ -0,0 +1,95 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.zeppelin.java;
+
+import org.apache.zeppelin.interpreter.InterpreterContext;
+import org.apache.zeppelin.interpreter.InterpreterResult;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+
+import static org.junit.Assert.assertEquals;
+
+public class JavaInterpreterUtilsTest {
+
+    private final static String TABLE_RESULT_1 = "%table\n" +
+            "Word\tCount\n" +
+            "world\t5\n" +
+            "hello\t4";
+
+    private static JavaInterpreter java;
+    private static InterpreterContext context;
+
+    @BeforeClass
+    public static void setUp() {
+        Properties p = new Properties();
+        java = new JavaInterpreter(p);
+        java.open();
+        context = InterpreterContext.builder().build();
+    }
+
+    @AfterClass
+    public static void tearDown() {
+        java.close();
+    }
+
+    @Test
+    public void testDisplayTableFromSimpleMapUtil() {
+
+        Map<String, Long> counts = new HashMap<>();
+        counts.put("hello",4L);
+        counts.put("world",5L);
+
+        assertEquals(
+                TABLE_RESULT_1,
+                JavaInterpreterUtils.displayTableFromSimpleMap("Word", "Count", counts)
+        );
+
+    }
+
+    @Test
+    public void testStaticReplWithDisplayTableFromSimpleMapUtilReturnTableType() {
+
+        StringWriter writer = new StringWriter();
+        PrintWriter out = new PrintWriter(writer);
+        out.println("import java.util.HashMap;");
+        out.println("import java.util.Map;");
+        out.println("import org.apache.zeppelin.java.JavaInterpreterUtils;");
+        out.println("public class HelloWorld {");
+        out.println("  public static void main(String args[]) {");
+        out.println("    Map<String, Long> counts = new HashMap<>();");
+        out.println("    counts.put(\"hello\",4L);");
+        out.println("    counts.put(\"world\",5L);");
+        out.println("    System.out.println(JavaInterpreterUtils.displayTableFromSimpleMap(\"Word\", \"Count\", counts));");
+        out.println("  }");
+        out.println("}");
+        out.close();
+
+        InterpreterResult res = java.interpret(writer.toString(), context);
+
+        assertEquals(InterpreterResult.Code.SUCCESS, res.code());
+        assertEquals(InterpreterResult.Type.TABLE, res.message().get(0).getType());
+    }
+
+}