Java is like a skilled craftsman whose services are invaluable to the day-to-day operations of many businesses. When everything's running as expected, this powerful and versatile programming language helps companies stay ahead of the competition.
But when something goes wrong, it can feel like all your technical troubleshooting efforts have failed you–you find yourself trying to mend leaks in an old boat with paperclips and bubble gum. The good news is that several common Java issues pop up repeatedly, so learning how to troubleshoot these problems quickly should help keep things running smoothly for your business.
In this blog post, we'll look at some of the most common Java errors you may run into, analyze their root causes and discuss various fixes you can use to get back on track.
The Most Common Java Errors & Fixes
Error #1: Out of Memory
The java.lang.OutOfMemoryError is a warning that your application has attempted to store more data in memory than it can handle, leading to catastrophic failures from which the program cannot recover.
This error can occur for many reasons, such as:
- Java heap space could be too small.
- Java PermGen memory could be too small.
- Native libraries may have been loaded into Java heap space and are not being released.
- Java objects could be referenced too frequently.
Troubleshooting Tips:
- Increase the Java heap size by adding the -Xmx parameter to your Java command line. This will allow Java to allocate more memory for its objects.
- If Java is still running out of memory, consider optimizing your Java code or application architecture.
- Increase Java PermGen memory by adding the -XX:MaxPermSize parameter to your Java command line. This will allow Java to allocate more memory to its permanent generation.
- If Java is still running out of memory, you may consider reducing the number of native libraries loaded into Java memory.
- If Java objects are referenced too frequently, you may need to consider using caching or other performance optimization techniques to reduce the frequency of Java object references.
Error #2: Java Exceptions
Java exceptions can be caused by a variety of factors, including syntax errors, logic errors, and resource exhaustion. Java exceptions can often be traced back to the original Java code, so a good understanding of Java and its libraries are essential for troubleshooting this type of error.
Common Java Exceptions & Fixes:
- NullPointerException – This exception is thrown when Java attempts to access an item with a 'null' reference value. The best way to fix this is by first determining what Java object was used in the code that caused the exception and then ensuring that Java has valid access.
- ArrayIndexOutOfBoundsException – This exception is thrown when Java attempts to access an item out of bounds in an array. The best way to fix this is by first determining which Java array was used in the code that caused the exception and then ensuring Java is accessing an item within its defined bounds.
- IllegalArgumentException – This exception is thrown when Java attempts to pass an invalid argument to a function or method. The best way to fix this is by first determining which Java function or method was called in the code that caused the exception and then ensuring Java passes valid arguments.
Other Troubleshooting Tips:
- Review your Java code and identify the cause of the exception. If you cannot spot it, consider using a Java profiler to help you analyze the code.
- Check Java system logs for additional information about the exception and possible causes.
- If necessary, use Java debuggers to track errors in your Java code.
Error #3: Java Performance Issues
Various factors, including inefficient code, slow network connections, and resource contention can cause Java performance issues. Java profiling tools are essential for identifying performance bottlenecks and resolving them.
Troubleshooting Tips:
- Check Java system logs to identify possible causes of Java performance issues.
- Use Java profiling tools to identify which Java methods and objects are taking too long to process.
- Optimize Java code by restructuring Java objects, reducing method calls and loop iterations, or using caching.
- If necessary, use Java debuggers to troubleshoot Java performance issues.
- Check network connections and ensure Java can access resources quickly.
- Adjust Java system parameters such as Heap size or Thread pool size to improve Java's performance.
Error #4: Java Security Issues
Java security issues are caused by Java applications not properly validating input and output data. Java security problems can also be caused by Java applications not properly validating user access rights or Java vulnerabilities.
Troubleshooting Tips:
- Review Java code and identify potential Java security issues.
- Check Java system logs for additional information about the security issue and possible causes.
- Check Java libraries for known Java vulnerabilities, and update them to their latest version if necessary.
- Implement data validation rules in your Java application to protect against malicious input data.
- Ensure users have proper authorization levels when accessing Java applications.
- Use Java encryption tools like SSL to help secure Java web applications.
Error #5: Improper Data Caching
Data caching helps Java applications store frequently used data in memory instead of making multiple requests to the same data source. Java data caching issues can occur when Java applications are not caching data properly or when Java incorrectly caches old data.
Troubleshooting Tips:
- Check Java system logs to identify possible causes of Java caching issues.
- Review Java code and ensure that Java is correctly using data caches.
- Adjust Java system parameters such as Cache size or Timeout length to improve Java caching performance.
- Ensure Java applications correctly evict old data from the cache when necessary.
- If necessary, use Java debuggers to troubleshoot Java caching issues.
- Use Java profiling tools to identify which Java methods and objects are taking too long to process due to improper data caching.
By following these tips, Java developers can quickly identify and resolve Java troubleshooting issues, ensuring the smooth operation of Java applications. With proper Java troubleshooting practices in place, Java developers can minimize Java application errors, improve Java performance and security, and ensure efficient data caching.
