diff --git a/packages/ant-util-tests/functions/objectLibFunction.js b/packages/ant-util-tests/functions/objectLibFunction.js
new file mode 100644
index 0000000..c4a6e9e
--- /dev/null
+++ b/packages/ant-util-tests/functions/objectLibFunction.js
@@ -0,0 +1,15 @@
+/**
+ * @fileoverview Object lib function for testing purposes.
+ */
+
+const { Observable } = require('rxjs');
+
+module.exports = () => {
+  return Observable.create(
+    subscriber => {
+      subscriber.next({ foo: 'bar' });
+      subscriber.complete();
+      return () => {};
+    }
+  );
+};
diff --git a/packages/ant/lib/config/Config.js b/packages/ant/lib/config/Config.js
index 7cb29fb..5377af6 100644
--- a/packages/ant/lib/config/Config.js
+++ b/packages/ant/lib/config/Config.js
@@ -813,7 +813,7 @@ provider "${providerName}"`
     }
     return Object.keys(functions).map(name => {
       const func = functions[name];
-      const { bin, handler, runtime } = func;
+      const { bin, handler, runtime, args } = func;
       try {
         if (bin) {
           return new BinFunction(runtimeController.ant, name, bin);
@@ -828,7 +828,7 @@ provider "${providerName}"`
           } else {
             runtimeInstance = runtimeController.defaultRuntime;
           }
-          return new LibFunction(runtimeController.ant, name, handler, runtimeInstance);
+          return new LibFunction(runtimeController.ant, name, handler, runtimeInstance, args);
         }
         throw new AntError(`Function type unknown: ${JSON.stringify(func)}`);
       } catch (e) {
diff --git a/packages/ant/lib/functions/LibFunction.js b/packages/ant/lib/functions/LibFunction.js
index ea3d6a1..0b731b2 100644
--- a/packages/ant/lib/functions/LibFunction.js
+++ b/packages/ant/lib/functions/LibFunction.js
@@ -25,7 +25,7 @@ class LibFunction extends AntFunction {
    * @throws {AssertionError} If "ant", "name", "handler" or "runtime" params
    * are not valid.
    */
-  constructor(ant, name, handler, runtime) {
+  constructor(ant, name, handler, runtime, args) {
     super(ant, name);
 
     assert(
@@ -51,6 +51,13 @@ class LibFunction extends AntFunction {
      * @private
      */
     this._runtime = runtime;
+
+    /**
+     * Contains the fixed arguments that will be used when running the function.
+     * @type {Array<String>}
+     * @private
+     */
+    this._args = args || [];
   }
 
   /**
@@ -71,6 +78,15 @@ class LibFunction extends AntFunction {
     return this._runtime;
   }
 
+  /**
+   * Contains the function fixed execution argumnets.
+   * @type {Array<String>}
+   * @readonly
+   */
+  get args() {
+    return this._args;
+  }
+
   /**
    * Runs the function. It can receive different arguments depending on the
    * function instance.
@@ -80,16 +96,22 @@ class LibFunction extends AntFunction {
   run() {
     logger.log(`Running lib function ${this.name}...`);
 
+    const args = JSON.stringify(
+      this._args.concat(Array.from(arguments))
+    );
     try {
       return this._runtime.run([
         this._handler,
-        JSON.stringify(Array.from(arguments))
+        args
       ]).pipe(map(data => {
         // JSON fails to parse 'undefined', but not '"undefined"'
         try {
           return JSON.parse(data);
         } catch (e) {
-          return undefined;
+          if (typeof data === 'string' && data.trim() === 'undefined') {
+            return undefined;
+          }
+          return data;
         }
       }));
     } catch (e) {
diff --git a/packages/ant/spec/lib/config/Config.spec.js b/packages/ant/spec/lib/config/Config.spec.js
index 64e9024..c026bf8 100644
--- a/packages/ant/spec/lib/config/Config.spec.js
+++ b/packages/ant/spec/lib/config/Config.spec.js
@@ -1136,7 +1136,8 @@ Template category value is not an object!'
           },
           Foo: {
             handler: '/foo/bar',
-            runtime: 'python'
+            runtime: 'python',
+            args: ['--foo', '--bar']
           }
         };
         const runtimeController = {
@@ -1158,6 +1159,7 @@ Template category value is not an object!'
         expect(func).toBeInstanceOf(LibFunction);
         expect(func.name).toBe('Foo');
         expect(func.handler).toBe(functions.Foo.handler);
+        expect(func.args).toBe(functions.Foo.args);
 
         expect(runtimeController.getRuntime.mock.calls.length).toBe(2);
         expect(runtimeController.getRuntime.mock.calls[0][0]).toBe(functions.MyLib.runtime);
diff --git a/packages/ant/spec/lib/functions/LibFunction.spec.js b/packages/ant/spec/lib/functions/LibFunction.spec.js
index 557dab2..4d46e01 100644
--- a/packages/ant/spec/lib/functions/LibFunction.spec.js
+++ b/packages/ant/spec/lib/functions/LibFunction.spec.js
@@ -3,7 +3,7 @@
  */
 
 const path = require('path');
-const { Observable } = require('rxjs');
+const { Observable, of } = require('rxjs');
 const { toArray } = require('rxjs/operators');
 const Ant = require('../../../lib/Ant');
 const LibFunction = require('../../../lib/functions/LibFunction');
@@ -96,5 +96,26 @@ describe('lib/functions/LibFunction.js', () => {
         )).run();
       }).toThrowError('Could not run lib function fooLibFunction');
     });
+
+    test('should run and handle multiple types result', async () => {
+      // Mocks the runtime.run function
+      const mockRuntime = new Runtime(ant, 'mockRuntime', 'bin', [], undefined, '1');
+      const values = [
+        1,
+        'a',
+        true,
+        { foo: {
+          bar: false
+        }},
+        ['lorem', 'ipsum'],
+        undefined,
+        null
+      ];
+      mockRuntime.run = jest.fn(() => of(...values));
+      const typeslibAntFunction = new LibFunction(ant, 'foo', 'bar', mockRuntime);
+      const runReturn = typeslibAntFunction.run();
+      expect(await runReturn.pipe(toArray()).toPromise())
+        .toEqual(values);
+    });
   });
 });
diff --git a/plugins/ant-core/functions/javaRuntime.js b/plugins/ant-core/functions/javaRuntime.js
new file mode 100755
index 0000000..f4a05dc
--- /dev/null
+++ b/plugins/ant-core/functions/javaRuntime.js
@@ -0,0 +1,63 @@
+#!/usr/bin/env node
+
+/**
+ * @fileoverview Java runtime for Ant Framework.
+ */
+const { spawn, spawnSync } = require('child_process');
+const { parse } = require('path');
+const { argv, stdout, stderr } = process;
+
+/**
+ * Flushes the stdout and stderr and exits the process.
+ *
+ * @param {Number} code The status code
+ */
+const exit = code => {
+  // On "close", waits stdout and stderr to flush
+  // and then exits. If it is already done,
+  // the cb is called anyway
+  stdout.end(() => {
+    stderr.end(() => {
+      process.exit(code);
+    });
+  });
+};
+
+let javaFile = argv[2];
+const { dirname, name: fileName, ext } = parse(javaFile);
+
+let args = [];
+const options = {};
+if (ext === '.jar') {
+  args.push('-cp');
+} else if (ext === '.java') {
+  const { error, status, stderr: javacStderr, stdout: javacStdout } = spawnSync('javac', [javaFile]);
+  if (error) {
+    stdout.write(javacStdout);
+    stderr.write(javacStderr);
+    exit(status);
+  }
+  options.cwd = dirname;
+  javaFile = fileName;
+}
+args.push(javaFile);
+
+// Filters null or undefined arguments and non serializable items
+args = args.concat(JSON.parse(argv[3]))
+  .filter(arg => {
+    if (arg === undefined || arg === null) {
+      return false;
+    }
+    try {
+      JSON.stringify(arg);
+      return true;
+    } catch (err) {
+      return false;
+    }
+  })
+  .map(arg => typeof arg === 'string' ? arg : JSON.stringify(arg));
+
+const javaProgram = spawn('java', args, options);
+javaProgram.stdout.on('data', data => stdout.write(data.toString()));
+javaProgram.stderr.on('data', data => stderr.write(data.toString()));
+javaProgram.on('close', exit);
diff --git a/plugins/ant-core/lib/Core.js b/plugins/ant-core/lib/Core.js
index f85ada2..430c79e 100644
--- a/plugins/ant-core/lib/Core.js
+++ b/plugins/ant-core/lib/Core.js
@@ -53,6 +53,14 @@ class Core extends Plugin {
         ['js'],
         path.resolve(__dirname, '../templates/function/node.js.mustache'),
         '10'
+      ),
+      new Runtime(
+        this._ant,
+        'Java',
+        path.resolve(__dirname, '../functions/javaRuntime.js'),
+        ['jar', 'java'],
+        path.resolve(__dirname, '../templates/function/java.java.mustache'),
+        '8'
       )
     ];
   }
diff --git a/plugins/ant-core/spec/lib/Core.spec.js b/plugins/ant-core/spec/lib/Core.spec.js
index 0a7371a..ed6bc75 100644
--- a/plugins/ant-core/spec/lib/Core.spec.js
+++ b/plugins/ant-core/spec/lib/Core.spec.js
@@ -1836,9 +1836,9 @@ describe('lib/Core.js', () => {
         ];
         antCli._ant.runtimeController._runtimes = new Map();
         antCli._ant.runtimeController.loadRuntimes(runtimes);
-        antCli._yargs.parse('runtime ls');
+
         process.exit = jest.fn(code => {
-          expect(code).toEqual(1);
+          expect(code).toBe(0);
           expect(console.log.mock.calls.length).toBe(5);
           expect(console.log.mock.calls[0][0]).toBe('Listing all runtimes available \
 ([default] <name> <version> <bin> [extensions] [template]):');
@@ -1848,6 +1848,21 @@ describe('lib/Core.js', () => {
           expect(console.log.mock.calls[4][0]).toBe('lorem 2 /ipsum');
           done();
         });
+        antCli._yargs.parse('runtime ls');
+      });
+
+      test('should not show "runtime ls" friendly error when error is unknown', () => {
+        const handleErrorMessage = jest.spyOn(yargsHelper, 'handleErrorMessage');
+        const error = new Error('Mocked error');
+        const antCli = new AntCli();
+        antCli._ant.pluginController.getPlugin('Core').listRuntimes = jest.fn(async () => {
+          throw error;
+        });
+        process.exit = jest.fn(code => {
+          expect(code).toBe(1);
+          expect(handleErrorMessage).toHaveBeenCalledWith(error.message, error, 'runtime ls');
+        });
+        antCli._yargs.parse('runtime ls');
       });
     });
   });
diff --git a/plugins/ant-core/templates/function/java.java.mustache b/plugins/ant-core/templates/function/java.java.mustache
new file mode 100644
index 0000000..5d744b7
--- /dev/null
+++ b/plugins/ant-core/templates/function/java.java.mustache
@@ -0,0 +1,69 @@
+import java.lang.StringBuffer;
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.net.URLEncoder;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * An example class which invokes a RESTful API and returns its content
+ * to the Ant Framework GraphQL API.
+ */
+public class {{name}} {
+  /**
+   * The args[0] represents the field parameters from the GraphQL query.
+   */
+  public static void main(String[] args) throws IOException {
+    /**
+     * The parameters are stored in a stringified JSON object.
+     * So, in order to make use of them, we need to parse it.
+     */
+    String cityName = parseJson(args[0]);
+    try {
+      // Opening connection to the RESTful API
+      String url = "http://api.openweathermap.org/data/2.5/weather?q="
+        + URLEncoder.encode(cityName, "UTF-8")
+        + "&appid=464ddf23d2c714ee8ecbc5b39f1f7eae";
+      HttpURLConnection con = (HttpURLConnection) new URL(url).openConnection();
+      con.setRequestMethod("GET");
+
+      // Retrieving the response content
+      BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
+      String inputLine;
+      StringBuffer response = new StringBuffer();
+
+      while ((inputLine = in.readLine()) != null) {
+        response.append(inputLine);
+      }
+      in.close();
+
+      // Prints the response to the stdout, which Ant is watching.
+      System.out.print(response.toString());
+    } catch (Exception e) {
+      // If any exception occurs, we should also let Ant be aware of it.
+      System.out.print(e.toString());
+    }
+  }
+
+  /**
+   * Since this file is only for testing purposes and we aren't importing any
+   * external libs, we parse the JSON using a regex.
+   *
+   * In this example, we are expecting the "city" parameter. So
+   * all we need to do here is retrieve it from the JSON and return
+   * its value, which is a String.
+   */
+  public static String parseJson(jsonAsString) {
+    String cityJsonRegex = "(?:\\\"city\\\":\\\")(.*?)(?:\\\")";
+    Pattern pattern = Pattern.compile(cityJsonRegex);
+    Matcher matcher = pattern.matcher(jsonAsString);
+    if (matcher.find()) {
+      String cityName = matcher.group().split(":")[1].replaceAll("\\\"", "");
+      return cityName;
+    }
+    return null;
+  }
+}
diff --git a/plugins/ant-graphql/lib/GraphQL.js b/plugins/ant-graphql/lib/GraphQL.js
index a03353b..704978f 100644
--- a/plugins/ant-graphql/lib/GraphQL.js
+++ b/plugins/ant-graphql/lib/GraphQL.js
@@ -20,6 +20,7 @@ const Map = require('yaml/map').default;
 const Pair = require('yaml/pair').default;
 const Scalar = require('yaml/scalar').default;
 
+const { stdout, stderr } = process;
 const defaultServerPath = path.dirname(
   require.resolve('@back4app/ant-graphql-express')
 );
@@ -340,7 +341,7 @@ directory "${cwd}"`
     this._serverProcess.stdout.on('data', (data) => {
       data = data.toString();
 
-      console.log(`Server => ${data}`);
+      stdout.write(`Server => ${data}`);
 
       const successMessage = 'GraphQL API server listening for requests on ';
 
@@ -360,7 +361,7 @@ directory "${cwd}"`
     });
 
     this._serverProcess.stderr.on('data', (data) => {
-      console.error(`Server => ${data}`);
+      stderr.write(`Server => ${data}`);
     });
 
     const promise = new Promise((resolve, reject) => {
diff --git a/plugins/ant-graphql/spec/lib/GraphQL.spec.js b/plugins/ant-graphql/spec/lib/GraphQL.spec.js
index 7ea1717..f55d884 100644
--- a/plugins/ant-graphql/spec/lib/GraphQL.spec.js
+++ b/plugins/ant-graphql/spec/lib/GraphQL.spec.js
@@ -73,9 +73,7 @@ describe('lib/GraphQL.js', () => {
   });
 
   test('should fail if server crashes', async () => {
-    const originalError = console.error;
-    console.error = jest.fn();
-    expect.hasAssertions();
+    const write = jest.spyOn(process.stderr, 'write').mockImplementation(() => {});
     const bin = path.resolve(
       utilPath,
       'templates/crashServerTemplate/server.js'
@@ -92,10 +90,11 @@ describe('lib/GraphQL.js', () => {
       expect(e.message).toEqual(
         expect.stringContaining('Server process closed with code "1"')
       );
-      expect(console.error).toHaveBeenCalledWith(expect.stringContaining(
+      expect(write).toHaveBeenCalledWith(expect.stringContaining(
         'Crashed'
       ));
-      console.error = originalError;
+    } finally {
+      jest.restoreAllMocks();
     }
   });
 
@@ -177,10 +176,10 @@ describe('lib/GraphQL.js', () => {
     expect.hasAssertions();
     const originalExec = childProcess.exec;
     childProcess.exec = jest.fn();
-    const originalError = console.error;
-    const originalLog = console.log;
-    console.error = jest.fn();
-    console.log = jest.fn();
+    const originalErrWrite = process.stderr.write;
+    process.stderr.write = jest.fn();
+    const originalOutWrite = process.stdout.write;
+    process.stdout.write = jest.fn();
     const model = path.resolve(
       utilPath,
       'configs/graphQLPluginConfig/model.graphql'
@@ -192,18 +191,18 @@ describe('lib/GraphQL.js', () => {
     const server = { bin };
     const graphQL = new GraphQL(ant, { model, server });
     await graphQL.startService();
-    expect(console.error).toHaveBeenCalledWith(
+    expect(process.stderr.write).toHaveBeenCalledWith(
       expect.stringContaining('Some server error')
     );
-    expect(console.log).toHaveBeenCalledWith(
+    expect(process.stdout.write).toHaveBeenCalledWith(
       expect.stringContaining('Some other log')
     );
-    console.error = originalError;
-    console.log = originalLog;
+    process.stderr.write = originalErrWrite;
+    process.stdout.write = originalOutWrite;
     childProcess.exec = originalExec;
   });
 
-  test('should show success message', async (done) => {
+  test('should show success message', async () => {
     expect.hasAssertions();
     const originalCwd = process.cwd();
     process.chdir(path.resolve(
@@ -234,7 +233,6 @@ for requests on http://localhost:3000')
       expect(e.message).toEqual(
         expect.stringContaining('Server process closed')
       );
-      done();
     }
   });
 
@@ -912,7 +910,7 @@ plugins:
         const graphQL = new GraphQL(ant);
         graphQL.directiveController.loadDirectives([
           new Directive(ant, 'myDir1', 'myDef1', new AntFunction(ant, 'myFunc1', () => {})),
-          new Directive(ant, 'myDir2', 'myDef2', new LibFunction(ant, 'myFunc2', 'myHandler2', new Runtime(ant, 'myRuntime2', 'myBin2', ['foo'])))
+          new Directive(ant, 'myDir2', 'myDef2', new LibFunction(ant, 'myFunc2', 'myHandler2', new Runtime(ant, 'myRuntime2', 'myBin2', ['foo'], undefined, '1')))
         ]);
         graphQL.listDirectives();
         expect(console.log).toHaveBeenCalledTimes(3);