Can ThreadLocal cause memory leak?

Memory leak is caused when ThreadLocal is always existing. If ThreadLocal object could be GC, it will not cause memory leak. Because the entry in ThreadLocalMap extends WeakReference, the entry will be GC after ThreadLocal object is GC.

Does MDC use ThreadLocal?

Internally, MDC uses ThreadLocal and it has some predefined functionalities like adding a prefix to every log.

How do you fix a memory leak in Java?

While writing code, remember the following points that prevent the memory leak in Java.

1. Do not create unnecessary objects.
2. Avoid String Concatenation.
3. Use String Builder.
4. Do not store a massive amount of data in the session.
5. Time out the session when no longer used.
6. Do not use the System.

What is MDC used for?

MDC allows us to fill a map-like structure with pieces of information that are accessible to the appender when the log message is actually written. The MDC structure is internally attached to the executing thread in the same way a ThreadLocal variable would be.

Is log4j2 thread-safe?

Is log4j thread-safe? Yes, log4j is thread-safe. Log4j components are designed to be used in heavily multithreaded systems.

How do you analyze out of memory error in Java?

OutOfMemoryError: Java heap space. 1) An easy way to solve OutOfMemoryError in java is to increase the maximum heap size by using JVM options “-Xmx512M”, this will immediately solve your OutOfMemoryError.

What causes Java memory leaks?

The first scenario that might cause a Java memory leak is referencing a heavy object with a static field. We created our ArrayList as a static field – which will never be collected by the JVM Garbage Collector during the lifetime of the JVM process, even after the calculations it was used for are done.

How does thread local storage work?

With thread local storage (TLS), you can provide unique data for each thread that the process can access using a global index. One thread allocates the index, which can be used by the other threads to retrieve the unique data associated with the index.

What is MDC in Java?

A Mapped Diagnostic Context, or MDC in short, is an instrument for distinguishing interleaved log output from different sources. Log output is typically interleaved when a server handles multiple clients near-simultaneously.