Three lines of code to simply modify the project code of the jar package

demand

Because the company does not give permission to the project , Unable to get the project directly , Now it needs to be modified jar A picture of the package , Directly in jar Package and modify will report an error

The process

ERROR 2022-06-24 16:27:02.398 [Tomcat-startStop-1] org.apache.catalina.core.ContainerBase[line:181] - A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[]]

If you modify it directly jar The package code will report an error Let you recompile , And I just need to replace the picture

result

Finally, find a way online Just unzip and package it in the virtual machine .

decompression jar package

mkdir aaa
unzip classes.jar -d ./aaa
12

modify aaa After the contents in the folder , Get into aaa Folder

Strike again jar package

jar -cfM0 new-classes.jar ./*