What is the difference between stack and heap memory in Java?
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In Java programming language, there are two main types of memory: stack memory and heap memory. Stack memory stores primitive variables and object references, while heap memory stores actual objects and arrays. Stack is faster for allocation but heap has larger size capacity.
Let's see memory allocation in action with a Java example. When we declare int x equals ten, it goes directly to stack memory. When we create a String or Person object, the reference is stored in stack but the actual object data goes to heap memory. Arrays work similarly with reference in stack and data in heap.
To summarize: Stack memory is faster but limited in size, while heap memory is larger but slower to access. References are always stored in stack memory, but object data goes to heap memory. Understanding these memory types helps optimize Java programs.
Let's see memory allocation in action with a Java example. When we declare int x equals ten, it goes directly to stack memory. When we create a String or Person object, the reference is stored in stack but the actual object data goes to heap memory. Arrays work similarly with reference in stack and data in heap.
Stack memory follows LIFO principle and is thread-specific with fast allocation but limited size. When full, it throws StackOverflowError. Heap memory is shared among threads, managed by Garbage Collector, slower than stack but has larger size. When full, it throws OutOfMemoryError.
Memory management in Java follows a specific lifecycle. Variables are declared and allocated in stack. Objects are created using new keyword and allocated in heap. Method execution creates stack frames which are removed when methods complete. When objects are no longer referenced, garbage collection frees the memory for reuse.
To summarize the key differences: Stack memory stores primitives and references with fast access but limited size. Heap memory stores objects and arrays with larger capacity but slower access. Stack follows LIFO principle and is thread-specific, while heap is shared among threads and managed by garbage collector. Understanding these memory types helps optimize Java program performance.