Oracle Java 1Z0-831 glossary of Java 25 language, constructors, streams, modules, and concurrency terms.
Keep this glossary nearby when Java 25 terms start to blend together. The guide punishes fuzzy vocabulary because fuzzy vocabulary usually hides fuzzy reasoning.
Automatic conversion between a primitive and its wrapper type such as int and Integer.
Java 25 source-file model for simple launchable programs without a traditional explicit top-level class declaration in the usual form.
The order elements are seen while iterating or streaming, which can affect results for ordered operations.
Compile-time removal of most generic type information from runtime class metadata.
Java 25 constructor model that allows certain statements before an explicit super(...) or this(...) invocation.
An interface with one abstract method, suitable for lambdas and method references.
Reusable custom intermediate stream operation model available in the Java 25 stream libraries.
A concurrency ordering rule that determines when one thread’s writes are guaranteed visible to another.
Unable to change after construction. Strings and many exam example values behave this way.
Preview Java language feature for importing exported packages from a module more succinctly.
Short rule for wildcard direction: producer extends, consumer super.
A feature that is fully specified enough to ship, but not yet permanent and still requiring preview enablement rules.
Concise Java type for modeling data with generated constructor, accessors, equals, hashCode, and toString.
Bounded context-sharing model for threads and subtasks, positioned as a safer alternative to many thread-local use cases.
A gatherer used with Stream.gather(...) to create custom intermediate stream behavior.
API model that treats related concurrent subtasks as one bounded unit of work.
The stream operation that actually triggers evaluation, such as collect, count, or forEach.
Collection view or factory result that rejects structural modification attempts.
Lightweight thread model in modern Java designed for large numbers of concurrent blocking tasks.
Generic placeholder type such as ?, ? extends T, or ? super T.
| Pair | Keep this distinction clear |
|---|---|
| collector vs gatherer | terminal reduction shape versus intermediate stream transformation |
| preview vs permanent | feature-status rule versus normal baseline Java behavior |
| scoped value vs thread-local | bounded context-sharing model versus thread-scoped storage model |
| structured concurrency vs executor usage | bounded task-family model versus general task execution strategy |
| flexible constructor body vs ordinary constructor code | special Java 25 constructor prologue rules versus normal body reasoning |
| record vs ordinary class | concise data-carrier form versus full manual class shape |
| Topic family | Best page to revisit |
|---|---|
| high-yield contrasts and decision rules | Cheat Sheet |
| current Oracle and Java 25 references | Resources |
| pacing and review order | Study Plan |
| overall exam framing | Guide root |