Develop Reference

App Crashes with no Stack Trace

Preface I've changed the title. It is hard to understand why, while debugging, sometimes uncaught exceptions print 'FATAL EXCEPTION' to the Logcat and sometimes they don't.
The simplified example below crashes when I get to the line client1.getInputStream(). There is no stack trace or other indication inside of Logcat as to what went wrong. I am running Android Studio 3.0.0beta4.
Why is it crashing? (update - crash was due to a SecurityException)
And why does Logcat not show a stack trace or
other error?
Update
Okay, I figured out why it crashes. I added catch(Exception ex) {...} and found that an exception was in fact being thrown, for I had forgotten to test for it. Stupid error, I didn't include INTERNET permission in the manifest.
So, I would still like to know why I would get no error indication for the unhandle exception. The app just quietly disappears.
Edit One commenter says
In java, unhandled exceptions are not printed
Here is the logcat message when I force an unhandled NullPointerException
FATAL EXCEPTION: Thread-6729
Process: com.example.myapplication, PID: 30824
java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.InputStream java.net.URLConnection.getInputStream()' on a null object reference
at com.example.myapplication.MainActivity.GetDataAsyncFromPlaystore(MainActivity.java:79)
at com.example.myapplication.MainActivity$1$1.run(MainActivity.java:42)
at java.lang.Thread.run(Thread.java:818)
So, why not for SecurityException?
Edit2 Just to make things more confusing, I've discovered that when I set a break point prior to the exception point, then step through the code and step over the offending line (the one causing the SecurityException), the App abruptly terminates with with no indication as to why. If however, I hit F9 before reaching the offending line, I do, in fact, get a "FATAL EXCEPTION" message logged in Logcat. (Therefore, I've added back the "android-studio" tag to the question.)
So, same question, slightly different wording: Why does the exception print a 'FATAL EXCEPTION' message when debugging one way, but not the other?
The (simplified) code
public void GetDataFromWebsite()
{
Uri queryUri = Uri.parse("https://play.google.com/store/search?q=Planning&c=apps");
try {
URL queryUrl = new URL(queryUri.toString());
URLConnection client1 = queryUrl.openConnection();
InputStream in = client1.getInputStream();
Log.d("Test", "Okay");
} catch (MalformedURLException muex) {
Log.e("Test", "Malformed Url", muex);
} catch (IOException ioex) {
Log.e("Test", "IO Error", ioex);
// } catch(Exception ex) {
// Log.e("Test","Other Exception", ex);
}
}
NOTE:

You are just catching MalformedURLException and IOException. So you won't get other exceptions.
Catch with Exception you will get a trace.
UnHandled exception not printed in android log cat. you can print UnHandled exception by UncaughtExceptionHandler. Here is a like to implement UncaughtExceptionHandler: Logging unhandled exceptions in Android Activity
There is no relativity between NullpointerException and SecurityException. How it will get caught by SecurityException.

Hide thrown exception messages on Android

Is there a way to block the displaying of thrown exception messages (with all the stacktrace and everything) for an android app ?
EDIT:
Well, I know I can use try/catch block to do that that's not what I want.
Is there like a way to specify that in mafinest file or maybe in project settigs or smthng ?

you can wrap your code in try catch
try {
// code that might throw an exception
} catch (Exception e) {
//don't print the exception
}

Logcat not showing exception stack trace

Logcat prints a single line with just the message and no exception stack trace. I am passing the exception e to the Log.i function. It used to work before. Now I can only see the stack trace using e.printStackTrace() which prints it to system.err.
catch (final IOException e) {
Log.i(TAG, "Error connecting to server.", e);
}
I think it may be because my current project is an Android Library and not an Application.
It's supposed to look like this but instead I only get the very first line. In my case it says "Error connecting to server." in place of "FATAL EXCEPTION: main".

Android debugging exceptions

I have been working with Eclipse/Android development porting a game from windows for about a month now.
But I have been frustrated with some aspects of this Environment.
When I get an exception, very rarely does the debugger stop where it needs to.
I have tried adding Exception breakpoints, this helps hit a few errors in relevant code but still very hit and miss.
Visual studio always stops execution in the closest entry point to the throwing of the exception, and I really miss that.
Even a minor
myArrayList[outOfBounds]
does not stop on the line that caused the issue.
I would like to know what experienced android developers do to track down the cause of exceptions quickly.

Put a try{ block around the statements that are going to generate the exception and then in the catch do something like
catch (Exception e) {
System.out.println("Test \"" + arg +
"\" threw a " + e.getClass() +
"\n with message: " + e.getMessage());
}

You can use try - catch block. Whenever any exception comes your catch block will be executed so you can put alert or message in catch block to track your problem or you can use Exception parent class to trace your bug.
try{
Your code to execute
}catch(Exception e){
e.printStackTrace();
}
This will give you error log in your logcat.

How to catch IOException Error in eclispe for Android?

I want to catch an IOException Error and want to show it in the form of toast for android application development. But when ever i apply catch(IOexception e), after try block it says to throws (throws IOException) with function name after which i am to catch error message.. Please Provide Some assistance....

May be you desire to 'throws' catched exception above the call stack, and next, catch and process all exception in one place (or 'layer') of code?)