Oracle 1z0-830 Exam Syllabus Topics:
| Section | Weight | Objectives |
|---|---|---|
| Functional Programming and Streams | 15% | - Optional class, primitive streams - Lambda expressions, functional interfaces, method references - Stream API: create, intermediate/terminal operations, parallel streams, grouping, partitioning |
| Controlling Program Flow | 10% | - Decision constructs: if-else, switch expressions and statements, pattern matching - Loops: for, enhanced for, while, do-while, break, continue, return |
| Working with Arrays and Collections | 12% | - Declare, instantiate, initialize, use arrays and multidimensional arrays - Collections Framework: List, Set, Map, Deque, Queue, sorting, searching |
| Modules and Packaging | 5% | - Module system: module-info.java, exports, requires, provides, uses - Create and use JAR files, modular and non-modular builds |
| 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 |
| Using Object-Oriented Concepts | 20% | - Classes, records, objects, constructors, initializers, methods, fields, encapsulation - Overloading, overriding, Object class methods, immutable objects - Inheritance, abstract classes, sealed classes, interfaces, polymorphism - Enums, nested classes, local variable type inference |
| Java I/O and Localization | 5% | - File I/O, NIO.2, streams, readers/writers, serialization - Resource bundles, locale, formatting messages, numbers, dates |
| Handling Exceptions | 8% | - Create and use custom exceptions, throw, throws - Exception hierarchy, try-catch-finally, multi-catch, try-with-resources |
| Advanced Features and Annotations | 3% | - Annotations, built-in annotations, custom annotations - Generics, type parameters, wildcards, type erasure |
| Concurrency and Multithreading | 10% | - Thread lifecycle, Runnable, Callable, ExecutorService, virtual threads - Synchronization, locks, concurrent collections, thread safety |
Oracle Java SE 21 Developer Professional Sample Questions:
1. Given:
java
public class BoomBoom implements AutoCloseable {
public static void main(String[] args) {
try (BoomBoom boomBoom = new BoomBoom()) {
System.out.print("bim ");
throw new Exception();
} catch (Exception e) {
System.out.print("boom ");
}
}
@Override
public void close() throws Exception {
System.out.print("bam ");
throw new RuntimeException();
}
}
What is printed?
A) bim boom bam
B) bim bam followed by an exception
C) bim bam boom
D) bim boom
E) Compilation fails.
2. Given:
java
try (FileOutputStream fos = new FileOutputStream("t.tmp");
ObjectOutputStream oos = new ObjectOutputStream(fos)) {
fos.write("Today");
fos.writeObject("Today");
oos.write("Today");
oos.writeObject("Today");
} catch (Exception ex) {
// handle exception
}
Which statement compiles?
A) fos.writeObject("Today");
B) oos.write("Today");
C) fos.write("Today");
D) oos.writeObject("Today");
3. Given:
java
StringBuffer us = new StringBuffer("US");
StringBuffer uk = new StringBuffer("UK");
Stream<StringBuffer> stream = Stream.of(us, uk);
String output = stream.collect(Collectors.joining("-", "=", ""));
System.out.println(output);
What is the given code fragment's output?
A) -US=UK
B) US-UK
C) An exception is thrown.
D) =US-UK
E) US=UK
F) Compilation fails.
4. Given:
java
int post = 5;
int pre = 5;
int postResult = post++ + 10;
int preResult = ++pre + 10;
System.out.println("postResult: " + postResult +
", preResult: " + preResult +
", Final value of post: " + post +
", Final value of pre: " + pre);
What is printed?
A) postResult: 16, preResult: 15, Final value of post: 6, Final value of pre: 5
B) postResult: 15, preResult: 16, Final value of post: 6, Final value of pre: 6
C) postResult: 15, preResult: 16, Final value of post: 5, Final value of pre: 6
D) postResult: 16, preResult: 16, Final value of post: 6, Final value of pre: 6
5. Given:
java
var hauteCouture = new String[]{ "Chanel", "Dior", "Louis Vuitton" };
var i = 0;
do {
System.out.print(hauteCouture[i] + " ");
} while (i++ > 0);
What is printed?
A) An ArrayIndexOutOfBoundsException is thrown at runtime.
B) Chanel Dior Louis Vuitton
C) Compilation fails.
D) Chanel
Solutions:
| Question # 1 Answer: C | Question # 2 Answer: D | Question # 3 Answer: D | Question # 4 Answer: B | Question # 5 Answer: D |
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