In Java™ 2 SDK (J2SDK), Standard Edition, version 1.2 and higher, the extcheck tool detects version conflicts between a target JAR file and currently installed extension JAR files. It is compatible with the keytool that is supplied by Sun Microsystems, Inc.
The extcheck tool is available using the Qshell Interpreter.
For more information about the extcheck tool, see the extcheck tool by Sun Microsystems, Inc.