How can I convert a stack trace to a string?

Question

What is the easiest way to convert the result of Throwable.getStackTrace() to a string that depicts the stacktrace?

Answer 1

If you are developing for Android, a far easier way is to use this:

import android.util.Log;

String stackTrace = Log.getStackTraceString(exception); 

The format is the same as getStacktrace, for e.g.

09-24 16:09:07.042: I/System.out(4844): java.lang.NullPointerException
09-24 16:09:07.042: I/System.out(4844):   at com.temp.ttscancel.MainActivity.onCreate(MainActivity.java:43)
09-24 16:09:07.042: I/System.out(4844):   at android.app.Activity.performCreate(Activity.java:5248)
09-24 16:09:07.043: I/System.out(4844):   at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
09-24 16:09:07.043: I/System.out(4844):   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
09-24 16:09:07.043: I/System.out(4844):   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
09-24 16:09:07.043: I/System.out(4844):   at android.app.ActivityThread.access$800(ActivityThread.java:139)
09-24 16:09:07.043: I/System.out(4844):   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
09-24 16:09:07.043: I/System.out(4844):   at android.os.Handler.dispatchMessage(Handler.java:102)
09-24 16:09:07.043: I/System.out(4844):   at android.os.Looper.loop(Looper.java:136)
09-24 16:09:07.044: I/System.out(4844):   at android.app.ActivityThread.main(ActivityThread.java:5097)
09-24 16:09:07.044: I/System.out(4844):   at java.lang.reflect.Method.invokeNative(Native Method)
09-24 16:09:07.044: I/System.out(4844):   at java.lang.reflect.Method.invoke(Method.java:515)
09-24 16:09:07.044: I/System.out(4844):   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
09-24 16:09:07.044: I/System.out(4844):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)

Answer 2

Use Throwable.printStackTrace(PrintWriter pw) to send the stack trace to an appropriate writer.

import java.io.StringWriter;
import java.io.PrintWriter;

// ...

StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
e.printStackTrace(pw);
String sStackTrace = sw.toString(); // stack trace as a string
System.out.println(sStackTrace);

Answer 3

Printing stack trace to string

import java.io.PrintWriter;
import java.io.StringWriter;

public class StackTraceUtils {
    public static String stackTraceToString(StackTraceElement[] stackTrace) {
        StringWriter sw = new StringWriter();
        printStackTrace(stackTrace, new PrintWriter(sw));
        return sw.toString();
    }
    public static void printStackTrace(StackTraceElement[] stackTrace, PrintWriter pw) {
        for(StackTraceElement stackTraceEl : stackTrace) {
            pw.println(stackTraceEl);
        }
    }
}

It's useful when you want to print the current thread stack trace without creating instance of Throwable - but note that creating new Throwable and getting stack trace from there is actually faster and cheaper than calling Thread.getStackTrace.

Answer 4

If you don't want to use an external library and you're not developing for Android, you could create an 'extension' method like this:

public static String getStackTraceString(Throwable e) {
    return getStackTraceString(e, "");
}

private static String getStackTraceString(Throwable e, String indent) {
    StringBuilder sb = new StringBuilder();
    sb.append(e.toString());
    sb.append("\n");

    StackTraceElement[] stack = e.getStackTrace();
    if (stack != null) {
        for (StackTraceElement stackTraceElement : stack) {
            sb.append(indent);
            sb.append("\tat ");
            sb.append(stackTraceElement.toString());
            sb.append("\n");
        }
    }

    Throwable[] suppressedExceptions = e.getSuppressed();
    // Print suppressed exceptions indented one level deeper.
    if (suppressedExceptions != null) {
        for (Throwable throwable : suppressedExceptions) {
            sb.append(indent);
            sb.append("\tSuppressed: ");
            sb.append(getStackTraceString(throwable, indent + "\t"));
        }
    }

    Throwable cause = e.getCause();
    if (cause != null) {
        sb.append(indent);
        sb.append("Caused by: ");
        sb.append(getStackTraceString(cause, indent));
    }

    return sb.toString();
}

Answer 5

This should work:

StringWriter sw = new StringWriter();
e.printStackTrace(new PrintWriter(sw));
String exceptionAsString = sw.toString();

Answer 6

The solution is to convert the stackTrace of array to string data type. See the following example:

import java.util.Arrays;

try{

}catch(Exception ex){
    String stack = Arrays.toString(ex.getStackTrace());
    System.out.println("stack "+ stack);
}