Bug 377751 - [Compatibility] NPE in Command.executeWithChecks

Added null guard
diff --git a/bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/Command.java b/bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/Command.java
index f92dcb2..c74d928 100644
--- a/bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/Command.java
+++ b/bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/Command.java
@@ -467,8 +467,9 @@
 		final IHandler handler = this.handler;
 		// workaround for the division of responsibilities to get
 		// bug 369159 working
-		if ("org.eclipse.ui.internal.MakeHandlersGo".equals(handler.getClass() //$NON-NLS-1$
-				.getName())) {
+		if ((handler != null)
+				&& "org.eclipse.ui.internal.MakeHandlersGo".equals(handler.getClass() //$NON-NLS-1$
+								.getName())) {
 			return handler.execute(event);
 		}