OutOfMemory

OutOfMemory refers to a condition in which a program, process, or system is unable to allocate additional memory to satisfy a request. It can arise when the available memory in the runtime environment is exhausted, when memory is fragmented, or when the operating system limits the virtual or physical address space available to the process.

Common causes include memory leaks, where objects are inadvertently retained and never garbage collected; unbounded data growth due to large datasets or caching; excessive parallelism or large thread stacks; native memory usage that exceeds limits; and misconfigured memory settings such as overly small heap sizes or container limits. In operating systems with aggressive memory management, the OS may also trigger an OutOfMemory condition by denying allocation requests or by invoking an out-of-memory killer to terminate processes.

Different platforms describe the condition in platform-specific terms. In Java, an OutOfMemoryError is thrown when the JVM cannot allocate memory, with subtypes such as Java heap space, Metaspace, or Direct buffer memory. In .NET, an OutOfMemoryException indicates insufficient managed or unmanaged memory. In Python, MemoryError signals an inability to allocate memory for objects. C and C++ programs may handle allocation failures by returning null or throwing exceptions in some libraries.

Mitigation involves memory profiling and monitoring, optimizing algorithms and data structures, enabling streaming and lazy loading, reducing peak memory usage, and increasing available memory or limits. Garbage collection tuning, memory pool management, and, in some cases, refactoring to avoid large in-memory datasets are common strategies.