You might be thinking, why should a Java developer read a book on Performance tuning? When I first faced this question a long time back, I thought I will do it later, but I never got back to that for a long time. I realize my mistake of having a lack of knowledge on memory measurement, JVM tuning, and finding bottleneck only when I faced severe performance and scalability issues on our mission-critical, server-side financial application written in Java. It's true that when you really need it, you learn most, but those times are not the best time to learn fundamentals, in fact, those times are to apply and correct your misunderstanding.
Wednesday, October 1, 2025
Wednesday, July 9, 2025
How to Fix java.lang.OutOfMemoryError: GC overhead limit exceeded ? Example Solution
The java.lang.OutOfMemoryError: GC overhead limit exceeded is another type of OutOfMemoryError in Java which comes when JVM spent too much time doing garbage collection without any success. For example, if almost 98% of CPU for a Java process is busy doing GC and reclaims very less amount of Java heap space around 2%, then JVM throws "java.lang.OutOfMemoryError: GC overhead limit exceeded" error. Though, the definition of 98% CPU time may vary between different Garbage collectors and different JVM versions.
Labels:
core java
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error and exception
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garbage collection
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JVM Internals
Thursday, June 12, 2025
Difference between Stack and Heap memory in Java? Example
The difference between stack and heap memory is a common programming question asked by beginners learning Java or any other programming language. Stack and heap memory are two terms programmers start hearing once they started programming but without any clear and definite explanation. Lack of knowledge of what is a heap in Java and what is stack memory in Java results in misconceptions related to stack and heap. To add to this confusion, a stack is also a data structure that is used to store elements in LIFO(Last In First Out) order and is available in Java API as java.util.Stack.
Labels:
core java
,
core java interview question
,
JVM Internals
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