How to convert a stack trace to a string?

Learn how to convert a stack trace to a String which includes all the Stack Trace message?

Example of converting StackTrace to String in Java Program

In this tutorial we are going to learn different ways to convert StackTrace to String in Java program. This conversion is required if you want to save the message in custom log file for further analysis of log message. The e.getMessage() in Java program only returns small portion of the error, but if you want to see the detailed error then StackTrace will give you complete detail about the error in the program.

Here we are going to discuss about few methods which can be used for the conversion of StackTrack error message into String. You can use any of the following methods:

• Core Java Libraries
• Google Guava Library
• Arrays class
• Apache commons stack trace to String

Conversion of StackTrace with Java API

Here one example of converting StackTrace to String in Java:

package net.roseindia;

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

public class ExceptionToString {

	public static void main(String[] args) {
		try {
			String strNum = "hello";
			int i = Integer.parseInt(strNum);
		} catch (Exception e) {
			// e.printStackTrace();
			System.out.println(stackTraceToString(e));
		}
	}

	public static String stackTraceToString(Exception e) {
		StringWriter sw = new StringWriter();
		PrintWriter pw = new PrintWriter(sw);
		e.printStackTrace(pw);
		String sStackTrace = sw.toString();
		return sStackTrace;
	}
}

If you run the above program it will convert StackTrace to String and print following converted error message:

java.lang.NumberFormatException: For input string: "hello"
	at java.lang.NumberFormatException.forInputString(Unknown Source)
	at java.lang.Integer.parseInt(Unknown Source)
	at java.lang.Integer.parseInt(Unknown Source)
	at net.roseindia.ExceptionToString.main(ExceptionToString.java:11)

In the above example code we have used StringWriter and PrintWriter classes to make a function which converts StrackTrace to String.

We have created following function for the conversation of StackTrace into String:

public static String stackTraceToString(Exception e) {
	StringWriter sw = new StringWriter();
	PrintWriter pw = new PrintWriter(sw);
	e.printStackTrace(pw);
	String sStackTrace = sw.toString();
	return sStackTrace;
}

This function can be used from another class for the conversion of error message into String.

Google Guava Library for conversion of StackTrace into String

The Google Guava is utility library in Java which provides many classes and methods which can be used in general programming. In this tutorial we are going to use the Throwables.getStackTraceAsString(e) method for converting StackTrace into String in our Java program.

Method signature: static String getStackTraceAsString(Throwable throwable)

This method takes the Throwable object as parameter and then returns a string which includes result of toString() and full, recursive stack trace of throwable object. So, it returns complete error details in String format.

Here is complete example:

package net.roseindia;

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

import com.google.common.base.Throwables;

public class ExceptionToStringWithGoogleGuava {

public static void main(String[] args) {
	try {
		String strNum = "hello";
		int i = Integer.parseInt(strNum);
	} catch (Exception e) {
		// e.printStackTrace();
		System.out.println(stackTraceToString(e));
		//e.getMessage();
	}
}

public static String stackTraceToString(Exception e) {
	String strStackTrace = Throwables.getStackTraceAsString(e);
	return strStackTrace;
}
}

You can easily add Google Guava maven library by adding following dependency code into pom.xml file of your project:

<dependency>
  <groupId>com.google.guava</groupId>
  <artifactId>guava</artifactId>
  <version>21.0</version>
</dependency>

Apache maven is the easily method of managing dependency in Java projects. You can check more tutorials at Maven 3 Tutorials.

With Arrays Class

Following code can also be used:

import java.util.Arrays;

After import Arrays class you can use following code for conversion:

Arrays.toString(e.getStackTrace());

But this code is returning all the error message in one line. For example if you can this code it will give you following output:

[java.lang.NumberFormatException.forInputString(Unknown Source), java.lang.Integer.parseInt(Unknown Source), java.lang.Integer.parseInt(Unknown Source), net.roseindia.ExceptionToStringWithGoogleGuava.main(ExceptionToStringWithGoogleGuava.java:14)]

As you can see all the output is in one line.

Apache commons stack trace to String

The Apache commons library can also be used to convert stack trace to String in Java. Here is an example of converting Stack Trace to String using Apache commons library:

package net.roseindia;

import org.apache.commons.lang3.exception.ExceptionUtils;

public class ExceptionToStringWithGoogleGuava {

public static void main(String[] args) {
	try {
		String strNum = "hello";
		int i = Integer.parseInt(strNum);
	} catch (Exception e) {
		// e.printStackTrace();
		System.out.println(stackTraceToString(e));
	}
}

public static String stackTraceToString(Exception e) {
	String strStacktrace = ExceptionUtils.getStackTrace(e);
	return strStacktrace;
}
}

In this section we have explored various ways to convert Exception Stack Trace into String.

Here are more tutorials related to Exception handling in Java:

• Printing a Stack Trace to the Server Console - Example codes for printing the Stack Trace on the Sever Console.
• How to Print a Stack Trace Message - Simple example of printing Stack Trace message from a Java program.
• Java get Stack Trace as String - Getting the complete Stack Trace message in the form of String in Java.
• Java Exceptions Tutorials With Examples - Many tutorials of exception handling in Java, learn how to handle exception in Java program.
• What are Chained Exceptions? - Detailed introduction of Chained Exceptions in Java programming language.
• Java :Thread dumpStack - How to get Thread dump in Java program.
• User Defined Exception In Java - How to create user defined exception in Java programming language.
• Java Exception Class Hierarchy Diagram - Learn the Exception hierarchy in Java with the help of diagram.
• Java Conversion Examples - Converting Java objects into another in Java programming language. Learn data type conversion in Java with 100s of examples.

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