1Z0-830 series practice examsIn development
Oracle Certified Professional: Java SE Developer
The flagship Java credential on the current long-term support release: pass by value and wrapper comparison, interfaces carrying default and static methods, records and sealed types with pattern matching, override against overload resolution, and generics under erasure with producer extends and consumer super; then the collection implementations and their costs, lazy single-use streams and Optional, executors and virtual threads with visibility distinguished from atomicity, and try-with-resources with suppressed exceptions.
What you get
Papers are cut from the bank and weighted like the real exam, and no question appears in two of them. Every wrong answer comes back on later days until you have it right.
What the exam covers
| The type system, object orientation and generics | Not published |
| Collections, streams, concurrency and the platform | Not published |
Two sample questions
1. What is the difference between a List and a Set in the collections framework?
- A Set keeps order and duplicates; a List does not
- Both reject duplicates but only a List is ordered
- A List keeps order and duplicates; a Set does not — correct
- Both allow duplicates but only a Set is ordered
Why: A List is an ordered collection permitting duplicates and indexed access, while a Set holds distinct elements with no duplicates, which is the essential difference in their contracts.
2. A method assigns a new object to its parameter. What does the caller see afterwards?
- The caller's variable still refers to the original object — correct
- The caller's variable refers to the newly created object
- The original object is replaced in place by the new one
- The assignment fails to compile without a final parameter
Why: Java passes references by value, so reassigning the parameter rebinds only the local copy. Mutating the object the reference points at is visible; replacing it is not.
The real 1Z0-830 series exam
| Length | 90 minutes |
|---|---|
| Questions | 50 |
| Pass mark | Around 68%, published per exam version by Oracle |
| Price | Purchased per attempt through Oracle University |
| Recommended before you sit it | None enforced. Substantial Java programming experience is assumed. |
| Valid for | Does not expire, though it is tied to the release examined |
Exam facts as published by Oracle; always check the vendor’s page before you book.
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