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Complete Guide: Convert Stack Trace to String Java

Learn multiple methods to convert stack traces to strings in Java. Discover the easiest approaches using core Java and Apache Commons Lang with complete examples and best practices.

#apache-commons-lang #error-handling #exception-handling #java-programming #java-stacktrace #logging #string-conversion

10/31/2025, 05:02 AM

Question

How can I convert a stack trace to a string representation in Java? What is the easiest way to convert the result of Throwable.getStackTrace() to a string that depicts the full stack trace?

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To convert a stack trace to a string representation in Java, you can use either the core Java approach with StringWriter and PrintWriter or leverage libraries like Apache Commons Lang for a simpler solution. The easiest method is using ExceptionUtils.getStackTrace(Throwable) from Apache Commons Lang, which provides a single-line solution without manual string manipulation.

Core Java Approach with StringWriter and PrintWriter
Using Apache Commons Lang (Recommended)
Manual Method with StackTraceElement Array
Complete Examples
Comparison of Methods
Best Practices

Core Java Approach with StringWriter and PrintWriter

The most common way to convert a stack trace to a string using only core Java libraries involves creating a StringWriter and PrintWriter:

java

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

public class StackTraceConverter {
    public static String getStackTraceString(Throwable throwable) {
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        throwable.printStackTrace(pw);
        return sw.toString();
    }
}

This approach works by:

Creating a StringWriter to capture the output
Creating a PrintWriter that writes to the StringWriter
Calling printStackTrace() on the throwable, which automatically writes to the PrintWriter
Returning the contents of the StringWriter as a string

Important: The printStackTrace() method automatically handles nested exceptions (causes), making this approach comprehensive for the entire exception chain.

Using Apache Commons Lang (Recommended)

The easiest and most straightforward method is using Apache Commons Lang library:

java

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

public class StackTraceConverter {
    public static String getStackTraceString(Throwable throwable) {
        return ExceptionUtils.getStackTrace(throwable);
    }
}

Advantages of this approach:

Single line of code
No need to manage StringWriter and PrintWriter manually
Handles nested exceptions properly
Well-tested and widely used in the Java ecosystem

Maven dependency:

xml

<dependency>
    <groupId>commons-lang</groupId>
    <artifactId>commons-lang</artifactId>
    <version>2.6</version>
</dependency>

For modern projects using Apache Commons Lang 3.x:

xml

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.14.0</version>
</dependency>

Note that in Commons Lang 3.x, the method is still ExceptionUtils.getStackTrace(Throwable).

Manual Method with StackTraceElement Array

If you need more control over the formatting or want to avoid external dependencies, you can manually process the stack trace:

java

public class StackTraceConverter {
    public static String getStackTraceString(Throwable throwable) {
        StringBuilder result = new StringBuilder();
        result.append(throwable.toString());
        result.append("\n");
        
        // Add each element of the stack trace
        for (StackTraceElement element : throwable.getStackTrace()) {
            result.append("\tat ");
            result.append(element.toString());
            result.append("\n");
        }
        
        // Handle nested exceptions
        Throwable cause = throwable.getCause();
        while (cause != null) {
            result.append("Caused by: ");
            result.append(cause.toString());
            result.append("\n");
            
            for (StackTraceElement element : cause.getStackTrace()) {
                result.append("\tat ");
                result.append(element.toString());
                result.append("\n");
            }
            
            cause = cause.getCause();
        }
        
        return result.toString();
    }
}

This method gives you full control over the formatting but requires more code and careful handling of nested exceptions.

Complete Examples

Here are complete working examples for each approach:

Example 1: Core Java Approach

java

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

public class StackTraceExample {
    public static void main(String[] args) {
        try {
            // Simulate an exception
            int result = 10 / 0;
        } catch (ArithmeticException e) {
            String stackTraceString = getStackTraceString(e);
            System.out.println("Stack Trace as String:");
            System.out.println(stackTraceString);
        }
    }
    
    public static String getStackTraceString(Throwable throwable) {
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        throwable.printStackTrace(pw);
        return sw.toString();
    }
}

Example 2: Apache Commons Lang Approach

java

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

public class StackTraceExample {
    public static void main(String[] args) {
        try {
            // Simulate an exception with nested cause
            throw new RuntimeException("Outer exception", new NullPointerException("Inner exception"));
        } catch (RuntimeException e) {
            String stackTraceString = ExceptionUtils.getStackTrace(e);
            System.out.println("Stack Trace as String:");
            System.out.println(stackTraceString);
        }
    }
}

Example 3: Try-with-Resources (Java 7+)

java

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

public class StackTraceExample {
    public static void main(String[] args) {
        try {
            // Simulate an exception
            String text = null;
            text.length();
        } catch (NullPointerException e) {
            String stackTraceString = getStackTraceString(e);
            System.out.println("Stack Trace as String:");
            System.out.println(stackTraceString);
        }
    }
    
    public static String getStackTraceString(Throwable throwable) {
        try (StringWriter sw = new StringWriter();
             PrintWriter pw = new PrintWriter(sw)) {
            throwable.printStackTrace(pw);
            return sw.toString();
        } catch (Exception e) {
            return throwable.toString();
        }
    }
}

Comparison of Methods

Method	Pros	Cons	Best For
StringWriter + PrintWriter	- No external dependencies - Handles nested exceptions - Well-tested	- More verbose - Requires resource management	Projects without external dependencies
Apache Commons Lang	- Single line of code - No resource management needed - Handles nested exceptions	- Requires external dependency	Most projects, especially when simplicity is key
Manual Method	- Full control over formatting - No external dependencies	- Complex implementation - Easy to make mistakes	Custom formatting requirements

Best Practices

Use Apache Commons Lang when possible - It’s the simplest and most reliable solution.
Handle resource management properly - When using StringWriter and PrintWriter, consider using try-with-resources (Java 7+) to ensure proper cleanup.
Consider performance - For high-performance applications, benchmark different approaches as there might be slight performance differences.
Handle nested exceptions - Ensure your solution properly handles getCause() and nested exceptions, as they are common in real-world applications.
Error handling - Always consider what happens if the conversion process itself fails.
Logging integration - When converting stack traces for logging, consider using your logging framework’s built-in exception handling capabilities, as they often have optimized implementations.

Example with nested exception handling:

java

public static String getFullStackTraceString(Throwable throwable) {
    StringWriter sw = new StringWriter();
    PrintWriter pw = new PrintWriter(sw);
    throwable.printStackTrace(pw);
    
    // The printStackTrace() method automatically handles nested exceptions,
    // so the above single line is sufficient for the complete stack trace
    return sw.toString();
}

Conclusion

Converting a stack trace to a string in Java can be accomplished through several methods, with Apache Commons Lang’s ExceptionUtils.getStackTrace() being the simplest and most recommended approach. For projects without external dependencies, the StringWriter and PrintWriter method provides a robust core Java solution. When choosing a method, consider your project’s requirements, dependencies, and the need for custom formatting. Remember that proper handling of nested exceptions is crucial for comprehensive stack trace representation.

Sources

How to handle nested exceptions when converting stack traces to strings in Java?What are the performance differences between different stack trace to string conversion methods in Java?How to customize the format of stack trace strings in Java applications?What are the best practices for logging stack traces in Java applications?How to convert stack traces to JSON format in Java?What are the alternatives to Apache Commons Lang for stack trace string conversion in Java?

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Complete Guide: Convert Stack Trace to String Java

Contents

Core Java Approach with StringWriter and PrintWriter

Using Apache Commons Lang (Recommended)

Manual Method with StackTraceElement Array

Complete Examples

Example 1: Core Java Approach

Example 2: Apache Commons Lang Approach

Example 3: Try-with-Resources (Java 7+)

Comparison of Methods

Best Practices

Conclusion

Sources