Data Types, Variables & Operators
Difficulty: easy
Overview
Java has 8 primitives: byte (8-bit, -128 to 127), short (16-bit), int (32-bit), long (64-bit), float (32-bit), double (64-bit), char (16-bit Unicode), boolean. Default instance values: numeric = 0, boolean = false, reference = null. Auto-boxing converts primitives to wrapper types (int → Integer). Integer division truncates. Operator precedence: *, /, % before +, -.
Practice Linked Questions
Q1. What is the default value of an instance variable of type int in Java?
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Q2. What is the size of the char data type in Java?
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Q3. Which of the following is NOT a primitive data type in Java?
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Q4. What is the result of: int x = 7 / 2; in Java?
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Q5. What is the output of: System.out.println(5 + 3 + "Java");
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Q6. What is auto-boxing in Java?
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Q7. What is the result of: 2 + 3 * 4 in Java?
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Q8. What is the valid range of a byte data type in Java?
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Q9. What is the output of the following code? int x = 10; System.out.println(x++); System.out.println(x);
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Q10. What is the output of the following code? int a = 5; int b = a++ + ++a; System.out.println(a + " " + b);
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Q11. What is the output of the following code? Integer a = 127; Integer b = 127; Integer c = 128; Integer d = 128; System.out.println(a == b); System.out.println(c == d); System.out.println(a.equals(b));
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Q12. What is the output of the following code? int x = 2; switch (x) { case 1: System.out.println("One"); case 2: System.out.println("Two"); case 3: System.out.println("Three"); break; case 4: System.out.println("Four"); }
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Q13. What is the output of the following code? int x = 5; double result = (x > 3) ? 1 : 2.0; System.out.println(result);
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Q14. What is the output of the following code? char c = 'A'; c += 1; System.out.println(c); System.out.println((int) c);
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Q15. What is the output of the following code? int x = 10; String result = (x > 5) ? "Greater" : "Lesser"; System.out.println(result);
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Q16. What is the output of the following code? System.out.println(Integer.parseInt("42")); System.out.println(Integer.toBinaryString(10)); System.out.println(Integer.MAX_VALUE);
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Q17. What is the output of the following code? System.out.println((int) 9.99); System.out.println((int) -9.99);
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Q18. What is the output of the following code? int result = 0; for (int i = 0; i < 5; i++) { if (i == 3) break; result += i; } System.out.println(result);
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