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Oracle 1z1-830 Exam Syllabus Topics:

Section	Objectives
Topic 1: Annotations and JDBC	- Execute SQL operations and process results - Use built-in and custom annotations - Connect to databases using JDBC
Topic 2: Object-Oriented Programming	- Create and use classes, interfaces, enums, and records - Implement encapsulation and abstraction - Apply inheritance and polymorphism
Topic 3: Collections and Generics	- Apply generics and bounded types - Use sequenced collections and maps - Use List, Set, Map, Queue, and Deque implementations
Topic 4: Java I/O and NIO	- Read and write files - Use Path, Files, and related APIs - Process file system resources
Topic 5: Controlling Program Flow	- Use switch expressions and pattern matching - Work with records and sealed classes - Apply decision statements and loops
Topic 6: Handling Date, Time, Text, Numeric and Boolean Values	- Use String, StringBuilder, and related APIs - Work with primitive wrappers and number formatting - Use date, time, duration, period, and localization APIs
Topic 7: Java Concurrency	- Create and manage threads - Work with concurrent collections and executors - Use virtual threads
Topic 8: Functional Programming	- Use lambda expressions and method references - Process data using Stream API - Work with functional interfaces
Topic 9: Modules and Packaging	- Package and deploy applications - Manage dependencies and exports - Create and use Java modules
Topic 10: Exception Handling	- Handle checked and unchecked exceptions - Create custom exceptions - Use try-with-resources

Oracle Java SE 21 Developer Professional Sample Questions:

1. Given:
java
public class Test {
public static void main(String[] args) throws IOException {
Path p1 = Path.of("f1.txt");
Path p2 = Path.of("f2.txt");
Files.move(p1, p2);
Files.delete(p1);
}
}
In which case does the given program throw an exception?

A) File f1.txt exists while file f2.txt doesn't
B) Both files f1.txt and f2.txt exist
C) File f2.txt exists while file f1.txt doesn't
D) An exception is always thrown
E) Neither files f1.txt nor f2.txt exist

2. What does the following code print?
java
import java.util.stream.Stream;
public class StreamReduce {
public static void main(String[] args) {
Stream<String> stream = Stream.of("J", "a", "v", "a");
System.out.print(stream.reduce(String::concat));
}
}

A) Optional[Java]
B) Compilation fails
C) null
D) Java

3. Given:
java
public class OuterClass {
String outerField = "Outer field";
class InnerClass {
void accessMembers() {
System.out.println(outerField);
}
}
public static void main(String[] args) {
System.out.println("Inner class:");
System.out.println("------------");
OuterClass outerObject = new OuterClass();
InnerClass innerObject = new InnerClass(); // n1
innerObject.accessMembers(); // n2
}
}
What is printed?

A) Compilation fails at line n2.
B) Compilation fails at line n1.
C) markdown
Inner class:
------------
Outer field
D) Nothing
E) An exception is thrown at runtime.

4. Given:
java
Stream<String> strings = Stream.of("United", "States");
BinaryOperator<String> operator = (s1, s2) -> s1.concat(s2.toUpperCase()); String result = strings.reduce("-", operator); System.out.println(result); What is the output of this code fragment?

A) United-States
B) United-STATES
C) -UnitedSTATES
D) -UNITEDSTATES
E) UnitedStates
F) UNITED-STATES
G) -UnitedStates