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Oracle 1z1-830 Exam Syllabus Topics:
| Section | Objectives |
|---|---|
| Topic 1: Exception Handling | - Create custom exceptions - Use try-with-resources - Handle checked and unchecked exceptions |
| Topic 2: Handling Date, Time, Text, Numeric and Boolean Values | - Work with primitive wrappers and number formatting - Use String, StringBuilder, and related APIs - Use date, time, duration, period, and localization APIs |
| Topic 3: Functional Programming | - Work with functional interfaces - Process data using Stream API - Use lambda expressions and method references |
| Topic 4: Object-Oriented Programming | - Implement encapsulation and abstraction - Create and use classes, interfaces, enums, and records - Apply inheritance and polymorphism |
| Topic 5: Modules and Packaging | - Manage dependencies and exports - Package and deploy applications - Create and use Java modules |
| Topic 6: Collections and Generics | - Apply generics and bounded types - Use List, Set, Map, Queue, and Deque implementations - Use sequenced collections and maps |
| Topic 7: Annotations and JDBC | - Connect to databases using JDBC - Use built-in and custom annotations - Execute SQL operations and process results |
| Topic 8: Controlling Program Flow | - Work with records and sealed classes - Apply decision statements and loops - Use switch expressions and pattern matching |
| Topic 9: Java I/O and NIO | - Process file system resources - Use Path, Files, and related APIs - Read and write files |
| Topic 10: Java Concurrency | - Work with concurrent collections and executors - Use virtual threads - Create and manage threads |
Oracle Java SE 21 Developer Professional Sample Questions:
1. Given:
java
String textBlock = """
j \
a \t
v \s
a \
""";
System.out.println(textBlock.length());
What is the output?
A) 10
B) 12
C) 11
D) 14
2. Given:
java
DoubleSummaryStatistics stats1 = new DoubleSummaryStatistics();
stats1.accept(4.5);
stats1.accept(6.0);
DoubleSummaryStatistics stats2 = new DoubleSummaryStatistics();
stats2.accept(3.0);
stats2.accept(8.5);
stats1.combine(stats2);
System.out.println("Sum: " + stats1.getSum() + ", Max: " + stats1.getMax() + ", Avg: " + stats1.getAverage()); What is printed?
A) Sum: 22.0, Max: 8.5, Avg: 5.5
B) An exception is thrown at runtime.
C) Compilation fails.
D) Sum: 22.0, Max: 8.5, Avg: 5.0
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) -US=UK
D) Compilation fails.
E) US-UK
F) An exception is thrown.
4. Consider the following methods to load an implementation of MyService using ServiceLoader. Which of the methods are correct? (Choose all that apply)
A) MyService service = ServiceLoader.load(MyService.class).findFirst().get();
B) MyService service = ServiceLoader.load(MyService.class).iterator().next();
C) MyService service = ServiceLoader.getService(MyService.class);
D) MyService service = ServiceLoader.services(MyService.class).getFirstInstance();
5. Given:
java
Object input = 42;
String result = switch (input) {
case String s -> "It's a string with value: " + s;
case Double d -> "It's a double with value: " + d;
case Integer i -> "It's an integer with value: " + i;
};
System.out.println(result);
What is printed?
A) It throws an exception at runtime.
B) It's a double with value: 42
C) Compilation fails.
D) It's a string with value: 42
E) It's an integer with value: 42
F) null
Solutions:
| Question # 1 Answer: B | Question # 2 Answer: A | Question # 3 Answer: B | Question # 4 Answer: A,B | Question # 5 Answer: C |

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