Catch exception in Android

ILiz :

I receive an error in my Android Studio after calling a method. I'm more curious if the error is what I think it is or not. The error first tells about an unexpected response code 500 after wich it shuts down and gives a fatal exception.

I've been trying to get the exception that comes from the fatal exception but no luck. To my understanding, I cannot catch the unexpected response code 500.

The error

D/NetworkSecurityConfig: No Network Security Config specified, using platform default
E/Volley: [1668] BasicNetwork.performRequest: Unexpected response code 500 for (website)
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.geotask, PID: 14594
    java.lang.IllegalStateException
        at com.example.geotask.PSHandler$1.onErrorResponse(PSHandler.java:48)
        at com.android.volley.Request.deliverError(Request.java:617)
        at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:104)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Application terminated.

The code that gives the error

try {
    psHandler.addNewUser(name, LoginActivity.this, new RetrievedCallback<Void>() {
        @Override
        public void execute(Void input) {
            Intent intent;
            intent = new Intent(LoginActivity.this, MainActivity.class);
            Toast.makeText(LoginActivity.this, "New account created", Toast.LENGTH_SHORT).show();
            startActivity(intent);
            finish();
        }
    });
} catch (IllegalStateException e) {
}

I removed the website it refers to. As you can see I'm trying to catch the possible error that is given in the logcat, but I'm not sure if I'm capable. I would like to know if I'm capable of preventing the error from the logcat.

Julio E. Rodríguez Cabañas :

The reason why you cannot catch the exception is because you are trying to catch it outside the method where it actually happens:

try {
    psHandler.addNewUser(name, LoginActivity.this, new RetrievedCallback<Void>() {
        @Override
        public void execute(Void input) {
            throw new IllegalStateException();
        }
    });
} catch (IllegalStateException e) {
    // This line will never be reached because the exception 
    // is not thrown here, but inside the callback method
}

Instead, you should add the try/catch inside the callback method:

psHandler.addNewUser(name, LoginActivity.this, new RetrievedCallback<Void>() {
    @Override
    public void execute(Void input) {
        try {
            throw new IllegalStateException();
        } catch (IllegalStateException e) {
            // This line will be reached
        }
    }
});