In the jni function development, it is necessary to know the function signature of the called java function, and the operation can be completed in android studio.
First, build the project and get the build folder.
Open build->intermediates->javac in android studio:
Find the class that needs to be queried, right-click this class, and choose to use the command line to open:
Enter at the command line:
javap -s xxxx.class 
search successful:
