ff --git a/plugins/org.eclipse.dltk.ruby.debug/.classpath b/plugins/org.eclipse.dltk.ruby.debug/.classpath
index 64c5e31..ad32c83 100644
--- a/plugins/org.eclipse.dltk.ruby.debug/.classpath
+++ b/plugins/org.eclipse.dltk.ruby.debug/.classpath
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/J2SE-1.5"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.6"/>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="src" path="src"/>
 	<classpathentry kind="output" path="bin"/>
diff --git a/plugins/org.eclipse.dltk.ruby.debug/.settings/org.eclipse.jdt.core.prefs b/plugins/org.eclipse.dltk.ruby.debug/.settings/org.eclipse.jdt.core.prefs
index 416f4fb..8000cd6 100644
--- a/plugins/org.eclipse.dltk.ruby.debug/.settings/org.eclipse.jdt.core.prefs
+++ b/plugins/org.eclipse.dltk.ruby.debug/.settings/org.eclipse.jdt.core.prefs
@@ -1,11 +1,11 @@
 eclipse.preferences.version=1
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
-org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.5
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.6
 org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
-org.eclipse.jdt.core.compiler.compliance=1.5
+org.eclipse.jdt.core.compiler.compliance=1.6
 org.eclipse.jdt.core.compiler.debug.lineNumber=generate
 org.eclipse.jdt.core.compiler.debug.localVariable=generate
 org.eclipse.jdt.core.compiler.debug.sourceFile=generate
 org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
 org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
-org.eclipse.jdt.core.compiler.source=1.5
+org.eclipse.jdt.core.compiler.source=1.6
diff --git a/plugins/org.eclipse.dltk.ruby.debug/META-INF/MANIFEST.MF b/plugins/org.eclipse.dltk.ruby.debug/META-INF/MANIFEST.MF
index ed294c1..9a5c323 100644
--- a/plugins/org.eclipse.dltk.ruby.debug/META-INF/MANIFEST.MF
+++ b/plugins/org.eclipse.dltk.ruby.debug/META-INF/MANIFEST.MF
@@ -13,4 +13,4 @@ Eclipse-LazyStart: true
 Export-Package: org.eclipse.dltk.ruby.debug
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
-Bundle-RequiredExecutionEnvironment: J2SE-1.5
+Bundle-RequiredExecutionEnvironment: JavaSE-1.6
diff --git a/plugins/org.eclipse.dltk.ruby.debug/src/org/eclipse/dltk/ruby/debug/RubyDebugPreferenceInitializer.java b/plugins/org.eclipse.dltk.ruby.debug/src/org/eclipse/dltk/ruby/debug/RubyDebugPreferenceInitializer.java
index 7ceda5c..97638b5 100644
--- a/plugins/org.eclipse.dltk.ruby.debug/src/org/eclipse/dltk/ruby/debug/RubyDebugPreferenceInitializer.java
+++ b/plugins/org.eclipse.dltk.ruby.debug/src/org/eclipse/dltk/ruby/debug/RubyDebugPreferenceInitializer.java
@@ -1,3 +1,13 @@
+/*******************************************************************************
+ * Copyright (c) 2008, 2016 Red Hat Inc. and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     Red Hat Inc. - Use builtin debugger if ruby-debug is not installed
+ *******************************************************************************/
 package org.eclipse.dltk.ruby.debug;
 
 import org.eclipse.core.runtime.Preferences;
@@ -10,7 +20,7 @@ public class RubyDebugPreferenceInitializer extends
 	public void initializeDefaultPreferences() {
 		Preferences store = RubyDebugPlugin.getDefault().getPluginPreferences();
 
-		if (store.getDefaultString(RubyDebugConstants.DEBUGGING_ENGINE_ID_KEY) == null)
+		if (store.getDefaultString(RubyDebugConstants.DEBUGGING_ENGINE_ID_KEY).isEmpty())
 			store.setDefault(RubyDebugConstants.DEBUGGING_ENGINE_ID_KEY,
 					"org.eclipse.dltk.ruby.basicdebugger"); //$NON-NLS-1$