Basic Customization > Windchill Customization Basics > Managing Customizations > Best Practices for Customizing Files Supplied by PTC > Managing Client JAR Files > Using the Client JAR Architecture > Rebuilding Client JARs
  
Rebuilding Client JARs
The client JARs are built via the Java SDK's jar command and an Ant script (MakeJar.xml) that coordinates the builds of the client JARs and other related activities (e.g. consolidation of duplicate entries, removal of known inappropriate resources, and updating JPI cache versions.
To rebuild all of the new client JARs, one can simply type:
ant -f MakeJar.xml
from a command prompt in the <Windchill>/codebase directory.
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As a general rule, customizers should not use this command pattern, as it will rebuild the FCS jars and cause unnecessary downloads by clients that have already downloaded the FCS jars by this point. Instead, 'custUpdate' and 'dsuUpdate' targets, as described in the following sections, should be used.
If you are using Java 2 v1.4.x, then any resources listed in a .includes file which are not present in your codebase will result in an error. To remove any such resources from your .includes files, add the following to your MakeJar.xml command line:
-DremoveStaleEntries=true
Although it takes only a couple minutes or so to rebuild all client JARs, in most cases you are only testing an applet or two at a time. In this case you will wish to the faster Ant targets for individual applets. For instance, to rebuild all JARs loaded by a workflow applet, one would use (all on one line):
ant -f MakeJar.xml buildFullClientJars -DlogicalJarNames=wtWork
Omitting the '-DdoDeepBuild=true' argument would limit the rebuild to the wtWork JARs, i.e. it would not rebuild the wtApplet JARs and so forth.
To determine what actions a command would perform, without actually performing them, the following argument can be added to the command line for any of the MakeJar.xml targets:
-DtraceOnly=true
The MakeJar.xml script contains targets allowing a wide variety of JAR building and maintenance operations to be performed for one or more JARs or sets thereof. To obtain more information on these targets, execute the following command:
ant -f MakeJar.xml -projecthelp