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Oracle 1z0-830 Exam Syllabus Topics:
| Section | Weight | Objectives |
|---|---|---|
| Topic 1: Java I/O and Localization | 5% | - Resource bundles, locale, formatting messages, numbers, dates - File I/O, NIO.2, streams, readers/writers, serialization |
| Topic 2: Concurrency and Multithreading | 10% | - Synchronization, locks, concurrent collections, thread safety - Thread lifecycle, Runnable, Callable, ExecutorService, virtual threads |
| Topic 3: Advanced Features and Annotations | 3% | - Annotations, built-in annotations, custom annotations - Generics, type parameters, wildcards, type erasure |
| Topic 4: Handling Exceptions | 8% | - Exception hierarchy, try-catch-finally, multi-catch, try-with-resources - Create and use custom exceptions, throw, throws |
| Topic 5: Working with Arrays and Collections | 12% | - Collections Framework: List, Set, Map, Deque, Queue, sorting, searching - Declare, instantiate, initialize, use arrays and multidimensional arrays |
| Topic 6: Controlling Program Flow | 10% | - Decision constructs: if-else, switch expressions and statements, pattern matching - Loops: for, enhanced for, while, do-while, break, continue, return |
| Topic 7: Using Object-Oriented Concepts | 20% | - Inheritance, abstract classes, sealed classes, interfaces, polymorphism - Overloading, overriding, Object class methods, immutable objects - Classes, records, objects, constructors, initializers, methods, fields, encapsulation - Enums, nested classes, local variable type inference |
| Topic 8: Handling Date, Time, Text, Numeric and Boolean Values | 12% | - Manipulate text, text blocks, String, StringBuilder and StringBuffer - Use primitives and wrapper classes, evaluate expressions and apply type conversions - Use Date-Time API: LocalDate, LocalTime, LocalDateTime, Period, Duration, Instant, ZonedDateTime |
| Topic 9: Modules and Packaging | 5% | - Module system: module-info.java, exports, requires, provides, uses - Create and use JAR files, modular and non-modular builds |
| Topic 10: Functional Programming and Streams | 15% | - Lambda expressions, functional interfaces, method references - Stream API: create, intermediate/terminal operations, parallel streams, grouping, partitioning - Optional class, primitive streams |
Oracle Java SE 21 Developer Professional Sample Questions:
1. Given:
java
var deque = new ArrayDeque<>();
deque.add(1);
deque.add(2);
deque.add(3);
deque.add(4);
deque.add(5);
System.out.print(deque.peek() + " ");
System.out.print(deque.poll() + " ");
System.out.print(deque.pop() + " ");
System.out.print(deque.element() + " ");
What is printed?
A) 1 1 1 1
B) 1 1 2 2
C) 1 1 2 3
D) 1 5 5 1
E) 5 5 2 3
2. Given:
java
CopyOnWriteArrayList<String> list = new CopyOnWriteArrayList<>();
list.add("A");
list.add("B");
list.add("C");
// Writing in one thread
new Thread(() -> {
list.add("D");
System.out.println("Element added: D");
}).start();
// Reading in another thread
new Thread(() -> {
for (String element : list) {
System.out.println("Read element: " + element);
}
}).start();
What is printed?
A) It prints all elements, but changes made during iteration may not be visible.
B) Compilation fails.
C) It throws an exception.
D) It prints all elements, including changes made during iteration.
3. Given:
java
interface A {
default void ma() {
}
}
interface B extends A {
static void mb() {
}
}
interface C extends B {
void ma();
void mc();
}
interface D extends C {
void md();
}
interface E extends D {
default void ma() {
}
default void mb() {
}
default void mc() {
}
}
Which interface can be the target of a lambda expression?
A) B
B) D
C) E
D) None of the above
E) C
F) A
4. What do the following print?
java
public class Main {
int instanceVar = staticVar;
static int staticVar = 666;
public static void main(String args[]) {
System.out.printf("%d %d", new Main().instanceVar, staticVar);
}
static {
staticVar = 42;
}
}
A) 666 666
B) 666 42
C) 42 42
D) Compilation fails
5. Given:
java
StringBuilder result = Stream.of("a", "b")
.collect(
() -> new StringBuilder("c"),
StringBuilder::append,
(a, b) -> b.append(a)
);
System.out.println(result);
What is the output of the given code fragment?
A) acb
B) abc
C) cba
D) cacb
E) bca
F) cbca
G) bac
Solutions:
| Question # 1 Answer: C | Question # 2 Answer: A | Question # 3 Answer: D | Question # 4 Answer: C | Question # 5 Answer: C |






