Could not find Jar tool executable & Target was not a JDK root. System Library is not found.

After installing Proguard, the program is confused and packaged, but prompts could not find Jar tool executable. Follow the on-line method to change the path of the window->preference->java->installed JRE in eclipse to the path of the JDK, but it cannot be changed to indicate that target is not a JDK root. System Library is not found. Find a way on the internet, that is to rename the JDK directory, my JDK directory name is the JDK, change it to J2DK, the installed JRE can identify the JDK path. will be able to correctly confuse the packaging. I don't know why I have to change my name.

A new problem arises, however, that the J2ME program cannot be run in Eclipse and prompts create process failed when you select Run as. I think maybe Eclipse has not changed the path of the JDK in some places because I modified the directory name of the JDK. However, there is no location in the Eclipse configuration file to reference the JDK path. And WTK can not run, I think it may be wtk in the boot is to load the JVM, but the path of the JVM was changed by me, causing it to not read. Finally found in the WTK bin under the suffix named. vm files are saved with the JDK path, and the JDK directory name is the JDK, so I changed the directory name to J2DK to run the J2ME program correctly. (All the. vm files have to be modified oh, the quickest way is to reload the WTK, of course)