I have the following bit of code, used on Android and tested quite extensively about 6 months ago. It has been working fine and has never been the cause of any problems.
private static class CurrentClassGetter extends SecurityManager {
public String getClassName() {
return getClassContext()[1].getName();
}
}
The calling code:
//---Get my name (last part of class name)
System.out.println("Attempting to get class name");
msSimpleName = new CurrentClassGetter().getClassName();
Which, I notice, is the exact same bit of code recommended by someone in this SO answer here:
Getting the class name from a static method in Java
Since this code was written, I’ve updated my Android SDK from r14 to r16. I also downloaded all of the newer SDK packages, from API10 (Android 2.3.3) to API15 (Android 4.0.3). However, the above code which was working fine is now throwing this error:
02-22 16:18:26.779: W/System.err(2593): java.lang.NullPointerException
02-22 16:18:26.786: W/System.err(2593): at com.company.myCompany.mobile.android.myCompanyApp$CurrentClassGetter.getClassName(myCompanyApp.java:413)
02-22 16:18:26.806: W/System.err(2593): at com.company.myCompany.mobile.android.myCompanyApp.monitor(myCompanyApp.java:289)
02-22 16:18:26.806: W/System.err(2593): at com.company.myCompany.mobile.android.myCompanyApp.monitor(myCompanyApp.java:257)
02-22 16:18:26.826: W/System.err(2593): at com.gomez.appname.appnameActivity.onCreate(appnameActivity.java:22)
02-22 16:18:26.836: W/System.err(2593): at android.app.Activity.performCreate(Activity.java:4465)
02-22 16:18:26.846: W/System.err(2593): at android.app.InstAppentation.callActivityOnCreate(InstAppentation.java:1049)
02-22 16:18:26.856: W/System.err(2593): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
02-22 16:18:26.866: W/System.err(2593): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
02-22 16:18:26.876: W/System.err(2593): at android.app.ActivityThread.access$600(ActivityThread.java:123)
02-22 16:18:26.876: W/System.err(2593): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
02-22 16:18:26.896: W/System.err(2593): at android.os.Handler.dispatchMessage(Handler.java:99)
02-22 16:18:26.896: W/System.err(2593): at android.os.Looper.loop(Looper.java:137)
02-22 16:18:26.906: W/System.err(2593): at android.app.ActivityThread.main(ActivityThread.java:4424)
02-22 16:18:26.926: W/System.err(2593): at java.lang.reflect.Method.invokeNative(Native Method)
02-22 16:18:26.926: W/System.err(2593): at java.lang.reflect.Method.invoke(Method.java:511)
02-22 16:18:26.946: W/System.err(2593): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
02-22 16:18:26.946: W/System.err(2593): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
02-22 16:18:26.956: W/System.err(2593): at dalvik.system.NativeStart.main(Native Method)
Basically, what you’re looking at is a call from onCreate in Android to my private API. Within the API, it’s trying to get the current class name using the above code.
The Target API version was 8 then and it’s 8 now (Android v2.2), so that has not changed at all. Java compliance level 1.6, running Java 1.6.0_24 64-bit.
Does anyone know why getClassContext()[1].getName() would be throwing a NullPointerException like this all of a sudden, when it worked before?
No fix in sight, I ended up removing this block of code entirely. It was only being used in debug output anyway and it wasn’t worth the research to figure out why this was failing.