Oracle 1z1-830 Exam Syllabus Topics:
| Section | Objectives |
|---|---|
| Annotations and JDBC | - Connect to databases using JDBC - Use built-in and custom annotations - Execute SQL operations and process results |
| Controlling Program Flow | - Use switch expressions and pattern matching - Work with records and sealed classes - Apply decision statements and loops |
| Object-Oriented Programming | - Create and use classes, interfaces, enums, and records - Implement encapsulation and abstraction - Apply inheritance and polymorphism |
| Exception Handling | - Handle checked and unchecked exceptions - Create custom exceptions - Use try-with-resources |
| Functional Programming | - Process data using Stream API - Work with functional interfaces - Use lambda expressions and method references |
| Java I/O and NIO | - Use Path, Files, and related APIs - Read and write files - Process file system resources |
| Handling Date, Time, Text, Numeric and Boolean Values | - Use String, StringBuilder, and related APIs - Use date, time, duration, period, and localization APIs - Work with primitive wrappers and number formatting |
| Modules and Packaging | - Manage dependencies and exports - Package and deploy applications - Create and use Java modules |
| Collections and Generics | - Use List, Set, Map, Queue, and Deque implementations - Use sequenced collections and maps - Apply generics and bounded types |
| Java Concurrency | - Use virtual threads - Work with concurrent collections and executors - Create and manage threads |
Oracle Java SE 21 Developer Professional Sample Questions:
Question 1
Given:
java
void verifyNotNull(Object input) {
boolean enabled = false;
assert enabled = true;
assert enabled;
System.out.println(input.toString());
assert input != null;
}
When does the given method throw a NullPointerException?
A. Only if assertions are enabled and the input argument is null
B. A NullPointerException is never thrown
C. Only if assertions are disabled and the input argument isn't null
D. Only if assertions are enabled and the input argument isn't null
E. Only if assertions are disabled and the input argument is null
Question 2
Which of the following can be the body of a lambda expression?
A. A statement block
B. Two statements
C. None of the above
D. Two expressions
E. An expression and a statement
Question 3
Given:
java
LocalDate localDate = LocalDate.of(2020, 8, 8);
Date date = java.sql.Date.valueOf(localDate);
DateFormat formatter = new SimpleDateFormat(/* pattern */);
String output = formatter.format(date);
System.out.println(output);
It's known that the given code prints out "August 08".
Which of the following should be inserted as the pattern?
A. MM d
B. MMM dd
C. MM dd
D. MMMM dd
Question 4
Given:
java
Integer frenchRevolution = 1789;
Object o1 = new String("1789");
Object o2 = frenchRevolution;
frenchRevolution = null;
Object o3 = o2.toString();
System.out.println(o1.equals(o3));
What is printed?
A. false
B. A NullPointerException is thrown.
C. true
D. Compilation fails.
E. A ClassCastException is thrown.
Question 5
Given:
java
public class Test {
class A {
}
static class B {
}
public static void main(String[] args) {
// Insert here
}
}
Which three of the following are valid statements when inserted into the given program?
A. A a = new Test().new A();
B. B b = new B();
C. B b = new Test().new B();
D. A a = new Test.A();
E. A a = new A();
F. B b = new Test.B();
Solutions:
| Question 1 Answer: E | Question 2 Answer: A | Question 3 Answer: D | Question 4 Answer: C | Question 5 Answer: A,B,F |
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