Troubleshooting "java.lang.OutOfMemoryError: PermGen Space" Error

Dealing with “java.lang.OutOfMemoryError: PermGen space” Error

The Java Virtual Machine (JVM) throws a java.lang.OutOfMemoryError: PermGen Space when the permanent generation of objects reaches an undesirable level. This can usually be attributed to the ever-increasing need for more memory as an application joins the “big data” club.

In this blog post, we’ll discuss what this error is and how you can go about fixing it.

What Is PermGen Space?

PermGen space (or permanent generation space) is a section of the JVM’s memory which stores "permanent" data such as class files and objects. When the Java application runs out of room in this space, the JVM will throw a java.lang.OutOfMemoryError: PermGen Space.

What Causes PermGen Space Error?

The root cause of the error is often related to memory usage that has become too large for the space available in the JVM. The most common causes of this issue are:

• Too many classes are being loaded into the JVM due to applications using very complex frameworks such as Spring or Hibernate.
• Too many libraries are included in the application or the application is using a version of the JVM that doesn’t have enough memory allocated for the PermGen space.

How to Fix the PermGen Space Issue

There are a few different options when it comes to fixing a java.lang.OutOfMemoryError: PermGen Space error.

• The first solution is to increase the amount of memory allocated for the PermGen space in the JVM. This can be done by passing in the -XX:MaxPermSize parameter when starting up the JVM.
• Another option is to use a garbage collector tool to collect unused classes and objects. This will help reduce the amount of memory being used by the permanent generation space.
• Lastly, you can try reducing the number of classes and libraries that are being loaded into the JVM by restructuring the application architecture.

It’s important to note that not all of these solutions will work for every application, so it’s best to test them out and see which works best for your particular use case.

Conclusion

The java.lang.OutOfMemoryError: PermGen Space is an increasingly common error that occurs when the JVM’s memory needs exceed the amount of memory that has been allocated for the permanent generation space. It’s important to identify the root cause of the issue as soon as possible and to then choose the right solution depending on the particular application’s needs.