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Oracle 1z0-830 Exam Syllabus Topics:
| Section | Objectives |
|---|---|
| Exception Handling | - Use try-with-resources - Handle checked and unchecked exceptions - Create custom exceptions |
| Controlling Program Flow | - Apply decision statements and loops - Use switch expressions and pattern matching - Work with records and sealed classes |
| Collections and Generics | - Use List, Set, Map, Queue, and Deque implementations - Apply generics and bounded types - Use sequenced collections and maps |
| Modules and Packaging | - Create and use Java modules - Package and deploy applications - Manage dependencies and exports |
| Java Concurrency | - Use virtual threads - Work with concurrent collections and executors - Create and manage threads |
| Object-Oriented Programming | - Implement encapsulation and abstraction - Create and use classes, interfaces, enums, and records - Apply inheritance and polymorphism |
| Annotations and JDBC | - Use built-in and custom annotations - Execute SQL operations and process results - Connect to databases using JDBC |
| Functional Programming | - Work with functional interfaces - Process data using Stream API - Use lambda expressions and method references |
| Handling Date, Time, Text, Numeric and Boolean Values | - Work with primitive wrappers and number formatting - Use date, time, duration, period, and localization APIs - Use String, StringBuilder, and related APIs |
| Java I/O and NIO | - Read and write files - Use Path, Files, and related APIs - Process file system resources |
Oracle Java SE 21 Developer Professional Sample Questions:
Which three of the following are correct about the Java module system?
- A. The unnamed module can only access packages defined in the unnamed module.
- B. If a package is defined in both a named module and the unnamed module, then the package in the unnamed module is ignored.
- C. We must add a module descriptor to make an application developed using a Java version prior to SE9 run on Java 11.
- D. Code in an explicitly named module can access types in the unnamed module.
- E. The unnamed module exports all of its packages.
- F. If a request is made to load a type whose package is not defined in any known module, then the module system will attempt to load it from the classpath.
Explanation: Only visible for ExamCost members. You can sign-up / login (it's free).
A module com.eiffeltower.shop with the related sources in the src directory.
That module requires com.eiffeltower.membership, available in a JAR located in the lib directory.
What is the command to compile the module com.eiffeltower.shop?
- A. css
CopyEdit
javac --module-source-path src -p lib/com.eiffel.membership.jar -s out -m com.eiffeltower.shop - B. bash
CopyEdit
javac -source src -p lib/com.eiffel.membership.jar -d out -m com.eiffeltower.shop - C. css
CopyEdit
javac --module-source-path src -p lib/com.eiffel.membership.jar -d out -m com.eiffeltower.shop - D. css
CopyEdit
javac -path src -p lib/com.eiffel.membership.jar -d out -m com.eiffeltower.shop
Explanation: Only visible for ExamCost members. You can sign-up / login (it's free).
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. 5 5 2 3
- E. 1 5 5 1
Explanation: Only visible for ExamCost members. You can sign-up / login (it's free).
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.write("Today");
- B. fos.writeObject("Today");
- C. oos.write("Today");
- D. oos.writeObject("Today");
Explanation: Only visible for ExamCost members. You can sign-up / login (it's free).
Which of the following statements are correct?
- A. You can use 'public' access modifier with all kinds of classes
- B. You can use 'private' access modifier with all kinds of classes
- C. You can use 'final' modifier with all kinds of classes
- D. You can use 'protected' access modifier with all kinds of classes
- E. None
Explanation: Only visible for ExamCost members. You can sign-up / login (it's free).
