Javac.exe terminated with code 2, but cannot be built.

I created the "Hello world" app to develop Android with Visual Studio 2015(VS)+Xamarin, but when I built it, I got the error "Javac.exe ended with code 2" and I couldn't build it.

After some research, I found that there was space in the Java path, so I uninstalled Java once, moved from C:\program files (x86)\Java\jdk to C:\Java\jdk, changed the environment variables, and passed the path of Xamarin's JDK in VS, but it didn't improve.

Please let me know if there is any way to correct this error.

The following are the specifications.
Operating System: Windows 10 Home (64bit)
VS 2015
JRE:ver1.8.0_231 Java HotSpot(TM) Client VM (build 25.231-b11, mixed mode, sharing)
JDK:javac13.0.1

I look forward to your kind cooperation.