diff --git a/tomcat-uidm/bin/setclasspath.bat b/tomcat-uidm/bin/setclasspath.bat
index 360b9e4..da0d8a3 100644
--- a/tomcat-uidm/bin/setclasspath.bat
+++ b/tomcat-uidm/bin/setclasspath.bat
@@ -15,61 +15,74 @@
 rem limitations under the License.
 
 rem ---------------------------------------------------------------------------
-rem Set CLASSPATH and Java options
+rem Set JAVA_HOME or JRE_HOME if not already set, ensure any provided settings
+rem are valid and consistent with the selected start-up options and set up the
+rem endorsed directory.
 rem ---------------------------------------------------------------------------
 
 rem Make sure prerequisite environment variables are set
-if not "%JAVA_HOME%" == "" goto gotJdkHome
+
+rem In debug mode we need a real JDK (JAVA_HOME)
+if ""%1"" == ""debug"" goto needJavaHome
+
+rem Otherwise either JRE or JDK are fine
 if not "%JRE_HOME%" == "" goto gotJreHome
+if not "%JAVA_HOME%" == "" goto gotJavaHome
 echo Neither the JAVA_HOME nor the JRE_HOME environment variable is defined
 echo At least one of these environment variable is needed to run this program
 goto exit
 
-:gotJreHome
-if not exist "%JRE_HOME%\bin\java.exe" goto noJavaHome
-if not exist "%JRE_HOME%\bin\javaw.exe" goto noJavaHome
-if not ""%1"" == ""debug"" goto okJavaHome
-echo JAVA_HOME should point to a JDK in order to run in debug mode.
-goto exit
-
-:gotJdkHome
+:needJavaHome
+rem Check if we have a usable JDK
+if "%JAVA_HOME%" == "" goto noJavaHome
 if not exist "%JAVA_HOME%\bin\java.exe" goto noJavaHome
 if not exist "%JAVA_HOME%\bin\javaw.exe" goto noJavaHome
 if not exist "%JAVA_HOME%\bin\jdb.exe" goto noJavaHome
 if not exist "%JAVA_HOME%\bin\javac.exe" goto noJavaHome
-if not "%JRE_HOME%" == "" goto okJavaHome
 set "JRE_HOME=%JAVA_HOME%"
-goto okJavaHome
+goto okJava
 
 :noJavaHome
-echo The JAVA_HOME environment variable is not defined correctly
-echo This environment variable is needed to run this program
-echo NB: JAVA_HOME should point to a JDK not a JRE
+echo The JAVA_HOME environment variable is not defined correctly.
+echo It is needed to run this program in debug mode.
+echo NB: JAVA_HOME should point to a JDK not a JRE.
 goto exit
-:okJavaHome
 
-if not "%BASEDIR%" == "" goto gotBasedir
-echo The BASEDIR environment variable is not defined
-echo This environment variable is needed to run this program
-goto exit
-:gotBasedir
-if exist "%BASEDIR%\bin\setclasspath.bat" goto okBasedir
-echo The BASEDIR environment variable is not defined correctly
-echo This environment variable is needed to run this program
-goto exit
-:okBasedir
+:gotJavaHome
+rem No JRE given, use JAVA_HOME as JRE_HOME
+set "JRE_HOME=%JAVA_HOME%"
 
+:gotJreHome
+rem Check if we have a usable JRE
+if not exist "%JRE_HOME%\bin\java.exe" goto noJreHome
+if not exist "%JRE_HOME%\bin\javaw.exe" goto noJreHome
+goto okJava
+
+:noJreHome
+rem Needed at least a JRE
+echo The JRE_HOME environment variable is not defined correctly
+echo This environment variable is needed to run this program
+goto exit
+
+:okJava
 rem Don't override the endorsed dir if the user has set it previously
 if not "%JAVA_ENDORSED_DIRS%" == "" goto gotEndorseddir
 rem Set the default -Djava.endorsed.dirs argument
-set "JAVA_ENDORSED_DIRS=%BASEDIR%\endorsed"
+set "JAVA_ENDORSED_DIRS=%CATALINA_HOME%\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 JRE_HOME may contain spaces.
+set _RUNJAVA="%JRE_HOME%\bin\java.exe"
+:gotRunJava
+
+rem Don't override _RUNJDB if the user has set it previously
 rem Also note the quoting as JAVA_HOME may contain spaces.
-set _RUNJAVA="%JRE_HOME%\bin\java"
-set _RUNJDB="%JAVA_HOME%\bin\jdb"
+if not "%_RUNJDB%" == "" goto gotRunJdb
+set _RUNJDB="%JAVA_HOME%\bin\jdb.exe"
+:gotRunJdb
 
 goto end