diff --git a/org.eclipse.jdt.launching/launching/org/eclipse/jdt/launching/JavaRuntime.java b/org.eclipse.jdt.launching/launching/org/eclipse/jdt/launching/JavaRuntime.java
index d9ca0f7..324ded1 100644
--- a/org.eclipse.jdt.launching/launching/org/eclipse/jdt/launching/JavaRuntime.java
+++ b/org.eclipse.jdt.launching/launching/org/eclipse/jdt/launching/JavaRuntime.java
@@ -3444,6 +3444,9 @@
 								else {
 									cliOptionBuffer.append(cliOptions);
 								}
+								if (cliOptionString.length() > 0 && cliOptionBuffer.length() > 0) {
+									cliOptionString.append(" "); //$NON-NLS-1$
+								}
 								cliOptionString.append(cliOptionBuffer);
 							}
 						}