Are there memory leaks in java

URLConnection; import java. Channels; import java. ReadableByteChannel; import java. MalformedURLException ;. URL ;. URLConnection ;. Channels ;. ReadableByteChannel ;. Charset ;. Connection; import java. PreparedStatement; import java. Easy to miss. Connection ;. PreparedStatement ;. SQLException ;. About the author. Bradley Kofi. Registered Last seen 9 months ago Vacancies Upmy Node. Stay Informed It's important to keep up with industry - subscribe!

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Log in to Reply. Well explained. Worth reading.. Categories Programming JavaScript Tips React Beginners Project Management Interview Human Resources Remote Job Python POS Tutorial React Lessons Trends Events We were observing the exact same behavior as before. This meant we had to dig even deeper. The next step was to look at the native memory usage and make sure everything that is allocated gets freed eventually. It provides a Java native interface that we can use in our application.

There was still no clear leak indicator and nothing changed in the memory usage pattern. With no clear indication so far, it was time to further analyze the memory usage with dedicated tools. First, we looked at the memory dumps in a memory profiler tool. The first dump was generated right after the application was started and had only a few requests. The second dump was generated right before the application reached 1GiB of heap usage.

We analyzed what was allocated and what could pose an issue in both instances. There was nothing out of the ordinary at first sight. Then, we decided to compare the objects on the heap that required the most memory. To our surprise, we had quite many requests and response objects stored on the heap.

Looking a bit deeper at this memory dump, we saw that we had 44 response objects stored on the heap which was much higher than in the initial dump. Every single one of these objects had a retained memory size in excess of 3MiB. Then it clicked. We allowed the application to use way too many threads for our use case. By default, a Spring Boot application uses a thread pool of size to process web requests. Because threads are only created on demand, the application begins with a small heap usage, but grows higher and higher with every new request.

This solved our memory issues for good. Now the heap is finally stable, and as a consequence GC is also faster. In the process of investigating and troubleshooting this issue, we used several tools that proved to be essential:. The first tool we already had at hand was the DataDog APM dashboard for JVM metrics which was very easy to use and allowed us to obtain the above graphs and dashboards.

Another tool we used for analyzing the heap usage and the native memory usage was the usage of the jemalloc library to profile calls to malloc. In order to be able to use jemalloc one needs to install it using apt-get install libjemalloc-dev and then inject it at runtime into the Java application:. To sum it up, I thought it was a memory leak. If you are interested in joining our engineering team, check out our open positions.

Home Page. Talented Podcast. Open Job Positions. GetYourGuide Magazine. Press Center. About Us. Contact Us. Sep Follow the four easy steps below to solve memory leaks:. For more information on memory leaks, Java, or other application processes, feel free to engage with us via the comments below or reach out to us here.

Your email address will not be published. This site uses Akismet to reduce spam. Learn how your comment data is processed. XTIVIA needs the contact information you provide to us to contact you about our products and services. You may unsubscribe from these communications at anytime, read our Privacy Policy here. Privacy Policy. Four Types of Memory Issues: Performance : Mostly associated with excessive object creation, deletion, delays in garbage collection, and so on.

Resource Constraints : When there is little memory available or more fragmentation of memory allocation for large objects. Java Heap Leaks : Java objects are created continuously without being released due to underlying object references. Native Memory Leaks: Continuously growing memory utilization outside the Java heap, such as allocations made by the Java native interface code or JVM allocations. Before finding memory leaks, you should know how and why they occur.

The developer is responsible for analyzing an application that consistently produces OutOfMemoryError. Assume after some investigation you found that an array instantiation was demanding too much memory. It was not an application fault, rather the application server was relying on the default heap size, which was too small.