Index: setclasspath.bat
===================================================================
--- setclasspath.bat	(revision 1616700)
+++ setclasspath.bat	(working copy)
@@ -65,11 +65,18 @@
 set "JAVA_ENDORSED_DIRS=%BASEDIR%\endorsed"
 :gotEndorseddir

+rem Don't override _RUNJAVA if the user has set it previously
+if not "%_RUNJAVA%" == "" goto gotRunJava
 rem Set standard command for invoking Java.
 rem Note that NT requires a window name argument when using start.
 rem Also note the quoting as JAVA_HOME may contain spaces.
 set _RUNJAVA="%JRE_HOME%\bin\java"
+:gotRunJava
+
+rem Don't override _RUNJDB if the user has set it previously
+if not "%_RUNJAVA%" == "" goto gotRunJdb
 set _RUNJDB="%JAVA_HOME%\bin\jdb"
+:gotRunJdb

 goto end

Index: setclasspath.sh
===================================================================
--- setclasspath.sh	(revision 1616700)
+++ setclasspath.sh	(working copy)
@@ -110,8 +110,12 @@
   fi
 fi

-# Set standard commands for invoking Java.
-_RUNJAVA="$JRE_HOME"/bin/java
-if [ "$os400" != "true" ]; then
-  _RUNJDB="$JAVA_HOME"/bin/jdb
+# Set standard commands for invoking Java, if not already set.
+if [ -z "$_RUNJAVA" ]; then
+  _RUNJAVA="$JRE_HOME"/bin/java
+  if [ "$os400" != "true" ]; then
+    if [ -z "$_RUNJDB" ]; then
+      _RUNJDB="$JAVA_HOME"/bin/jdb
+    fi
+  fi
 fi