diff --git a/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxFatJarMojo.java b/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxFatJarMojo.java
index 73f56b3..7d99fde 100644
--- a/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxFatJarMojo.java
+++ b/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxFatJarMojo.java
@@ -32,39 +32,43 @@
 import static org.vertx.java.platform.PlatformLocator.factory;
 
 @Mojo(name = "fatJar", requiresProject = true, threadSafe = false, requiresDependencyResolution =
-    COMPILE_PLUS_RUNTIME)
+		COMPILE_PLUS_RUNTIME)
 public class VertxFatJarMojo extends BaseVertxMojo {
 
-  @Parameter(property = "vertx.createFatJar", defaultValue = "false")
-  protected Boolean createFatJar;
+	@Parameter(property = "vertx.createFatJar", defaultValue = "false")
+	protected Boolean createFatJar;
 
-  @Override
-  public void execute() throws MojoExecutionException {
-    try {
-      if (createFatJar) {
-        System.setProperty("vertx.mods", modsDir.getAbsolutePath());
-        final PlatformManager pm = factory.createPlatformManager();
+	private static final Object lock = new Object();
 
-        final CountDownLatch latch = new CountDownLatch(1);
-        pm.makeFatJar(moduleName, project.getBasedir().getAbsolutePath() + "/target",
-            new Handler<AsyncResult<Void>>() {
-              @Override
-              public void handle(final AsyncResult<Void> event) {
-                if (event.succeeded()) {
-                  latch.countDown();
-                } else {
-                  if (!event.succeeded()) {
-                    getLog().error(event.cause());
-                  }
-                  latch.countDown();
-                }
-              }
-            });
-        latch.await(MAX_VALUE, MILLISECONDS);
-      }
-    } catch (final Exception e) {
-      throw new MojoExecutionException(e.getMessage());
-    }
-  }
+	@Override
+	public void execute() throws MojoExecutionException {
+		synchronized (lock) {
+			try {
+				if (createFatJar) {
+					System.setProperty("vertx.mods", modsDir.getAbsolutePath());
+					final PlatformManager pm = factory.createPlatformManager();
+
+					final CountDownLatch latch = new CountDownLatch(1);
+					pm.makeFatJar(moduleName, project.getBasedir().getAbsolutePath() + "/target",
+							new Handler<AsyncResult<Void>>() {
+								@Override
+								public void handle(final AsyncResult<Void> event) {
+									if (event.succeeded()) {
+										latch.countDown();
+									} else {
+										if (!event.succeeded()) {
+											getLog().error(event.cause());
+										}
+										latch.countDown();
+									}
+								}
+							});
+					latch.await(MAX_VALUE, MILLISECONDS);
+				}
+			} catch (final Exception e) {
+				throw new MojoExecutionException(e.getMessage());
+			}
+		}
+	}
 }
 
diff --git a/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxInitMojo.java b/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxInitMojo.java
index 87e622a..be81ae6 100644
--- a/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxInitMojo.java
+++ b/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxInitMojo.java
@@ -38,39 +38,42 @@
 @Mojo(name = "init", requiresProject = true, threadSafe = false, requiresDependencyResolution = COMPILE_PLUS_RUNTIME)
 public class VertxInitMojo extends BaseVertxMojo {
 
-  @Override
-  public void execute() throws MojoExecutionException {
+	private static final Object lock = new Object();
 
-    try {
-      setVertxMods();
+	@Override
+	public void execute() throws MojoExecutionException {
+		synchronized (lock) {
+			try {
+				setVertxMods();
 
-      File cpFile = new File("vertx_classpath.txt");
-      if (!cpFile.exists()) {
-        cpFile.createNewFile();
-        String defaultCp = "src/main/resources\r\n" +
-            "target/classes\r\n" +
-            "target/dependencies\r\n" +
-            "bin\r\n";
-        try (FileWriter writer = new FileWriter(cpFile)) {
-          writer.write(defaultCp);
-        }
-      }
+				File cpFile = new File("vertx_classpath.txt");
+				if (!cpFile.exists()) {
+					cpFile.createNewFile();
+					String defaultCp = "src/main/resources\r\n" +
+							"target/classes\r\n" +
+							"target/dependencies\r\n" +
+							"bin\r\n";
+					try (FileWriter writer = new FileWriter(cpFile)) {
+						writer.write(defaultCp);
+					}
+				}
 
-      final PlatformManager pm = factory.createPlatformManager();
+				final PlatformManager pm = factory.createPlatformManager();
 
-      final CountDownLatch latch = new CountDownLatch(1);
-      pm.createModuleLink(moduleName, new Handler<AsyncResult<Void>>() {
-        @Override
-        public void handle(AsyncResult<Void> asyncResult) {
-          if (!asyncResult.succeeded()) {
-            getLog().info(asyncResult.cause().getMessage());
-          }
-          latch.countDown();
-        }
-      });
-      latch.await(MAX_VALUE, MILLISECONDS);
-    } catch (final Exception e) {
-      throw new MojoExecutionException(e.getMessage(), e);
-    }
-  }
+				final CountDownLatch latch = new CountDownLatch(1);
+				pm.createModuleLink(moduleName, new Handler<AsyncResult<Void>>() {
+					@Override
+					public void handle(AsyncResult<Void> asyncResult) {
+						if (!asyncResult.succeeded()) {
+							getLog().info(asyncResult.cause().getMessage());
+						}
+						latch.countDown();
+					}
+				});
+				latch.await(MAX_VALUE, MILLISECONDS);
+			} catch (final Exception e) {
+				throw new MojoExecutionException(e.getMessage(), e);
+			}
+		}
+	}
 }
diff --git a/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxPullInDepsMojo.java b/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxPullInDepsMojo.java
index b7c73f6..c8a1815 100644
--- a/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxPullInDepsMojo.java
+++ b/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxPullInDepsMojo.java
@@ -15,39 +15,43 @@
 import static org.vertx.java.platform.PlatformLocator.factory;
 
 @Mojo(name = "pullInDeps", requiresProject = true, threadSafe = false, requiresDependencyResolution =
-    COMPILE_PLUS_RUNTIME)
+		COMPILE_PLUS_RUNTIME)
 public class VertxPullInDepsMojo extends BaseVertxMojo {
 
-  @Parameter(property = "vertx.pullInDeps", defaultValue = "false")
-  protected Boolean pullInDeps;
-
-  @Override
-  public void execute() throws MojoExecutionException {
-    if (pullInDeps) {
-      ClassLoader oldTCCL = Thread.currentThread().getContextClassLoader();
-      try {
-        setVertxMods();
-        Thread.currentThread().setContextClassLoader(createClassLoader());
-        PlatformManager pm = factory.createPlatformManager();
-
-        final CountDownLatch latch = new CountDownLatch(1);
-        pm.pullInDependencies(moduleName,
-          new Handler<AsyncResult<Void>>() {
-            @Override
-            public void handle(final AsyncResult<Void> event) {
-              if (!event.succeeded()) {
-                getLog().error(event.cause());
-              }
-              latch.countDown();
-            }
-          });
-        latch.await(MAX_VALUE, MILLISECONDS);
-
-      } catch (final Exception e) {
-        throw new MojoExecutionException(e.getMessage());
-      } finally {
-        Thread.currentThread().setContextClassLoader(oldTCCL);
-      }
-    }
-  }
+	private static final Object lock = new Object();
+
+	@Parameter(property = "vertx.pullInDeps", defaultValue = "false")
+	protected Boolean pullInDeps;
+
+	@Override
+	public void execute() throws MojoExecutionException {
+		synchronized (lock) {
+			if (pullInDeps) {
+				ClassLoader oldTCCL = Thread.currentThread().getContextClassLoader();
+				try {
+					setVertxMods();
+					Thread.currentThread().setContextClassLoader(createClassLoader());
+					PlatformManager pm = factory.createPlatformManager();
+
+					final CountDownLatch latch = new CountDownLatch(1);
+					pm.pullInDependencies(moduleName,
+							new Handler<AsyncResult<Void>>() {
+								@Override
+								public void handle(final AsyncResult<Void> event) {
+									if (!event.succeeded()) {
+										getLog().error(event.cause());
+									}
+									latch.countDown();
+								}
+							});
+					latch.await(MAX_VALUE, MILLISECONDS);
+
+				} catch (final Exception e) {
+					throw new MojoExecutionException(e.getMessage());
+				} finally {
+					Thread.currentThread().setContextClassLoader(oldTCCL);
+				}
+			}
+		}
+	}
 }
diff --git a/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxRunModMojo.java b/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxRunModMojo.java
index 5b8747e..3300f00 100644
--- a/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxRunModMojo.java
+++ b/plugin/src/main/java/org/vertx/maven/plugin/mojo/VertxRunModMojo.java
@@ -2,10 +2,13 @@
 
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
 import org.vertx.java.core.AsyncResult;
 import org.vertx.java.core.Handler;
 import org.vertx.java.platform.PlatformManager;
 
+import java.util.Collections;
+import java.util.Map;
 import java.util.concurrent.CountDownLatch;
 
 import static java.lang.Long.MAX_VALUE;
@@ -36,11 +39,21 @@
 @Mojo(name = "runMod", requiresProject = true, threadSafe = false, requiresDependencyResolution = COMPILE_PLUS_RUNTIME)
 public class VertxRunModMojo extends BaseVertxMojo {
 
+  /**
+   * List of system properties to set when running a module.
+   */
+  @Parameter
+  protected Map<String, String> systemPropertyVariables = Collections.emptyMap();
+
   @Override
   public void execute() throws MojoExecutionException {
 
     ClassLoader oldTCCL = Thread.currentThread().getContextClassLoader();
     try {
+      for (final Map.Entry<String, String> entry : systemPropertyVariables.entrySet()) {
+        System.setProperty(entry.getKey(), entry.getValue());
+	  }
+
       setVertxMods();
 
       Thread.currentThread().setContextClassLoader(createClassLoader());