OCP Study Guide 2026

The JPMS strictly prohibits the same package from being present in two different named modules; this causes a module resolution error.

A full backup combined with incremental backups generally provides the fastest recovery time. The full backup serves as a complete baseline, and subsequent incremental backups only capture changes since the last backup. During recovery, the full backup is restored first, and then the incremental backups are applied in sequence, bringing the database up to date efficiently.

The key distinction lies in their execution behavior. Intermediate operations (e.g., `filter`, `map`, `sorted`) are lazy; they don't execute until a terminal operation is invoked. They build up a pipeline of transformations, each returning a new `Stream`. Terminal operations (e.g., `forEach`, `collect`, `reduce`) are eager, triggering the processing of the entire pipeline and producing a final result, such as a collection, a single value, or a side-effect. Once a terminal operation is called, the stream is considered consumed and cannot be reused.

A bigfile tablespace contains a single datafile that can be up to 128TB, simplifying management by reducing the number of datafiles.

The Database Writer (DBWR) background process is responsible for writing modified data blocks from the database buffer cache to the data files on disk. This process ensures that changes made in memory are persistently stored, managing the flow of data from the volatile memory to stable storage. While SMON and PMON are also background processes, DBWR specifically handles writing dirty buffers.

SGA_TARGET enables Automatic Shared Memory Management (ASMM) and sets the total SGA size.