Java Guide: What is Heap Space & Dynamic Memory Allocation?

Java applications utilize the Java Virtual Machine (JVM) to manage memory through two primary areas: stack and heap memory. The heap space, created at the start of a JVM instance, is used for dynamic memory allocation of Java objects and classes during runtime and is divided into generations, including Young, Old, and Permanent (or Metaspace since Java 8). New objects are allocated in the Young Generation, which undergoes minor garbage collection, while long-surviving objects are transferred to the Old Generation, where major garbage collection occurs. The heap is slower to access compared to stack memory and requires the Garbage Collector to manage deallocation of unused objects, ensuring efficient memory use. The heap is globally accessible but not threadsafe, necessitating code synchronization. Heap size is controlled by JVM attributes -Xms and -Xmx, and exceeding available memory can lead to an OutOfMemoryError. Java applications rely on the heap for object storage throughout their runtime, and tools like Rollbar can assist in managing and monitoring errors for improved application reliability.