Certified Java Programmer Mock Exam

Question 1

class GRC7 {public void main(String[] args) {}} // 1
class GRC8 {public void main(String []args) {}} // 2
class GRC9 {public void main(String args[]) {}} // 3

What is the result of attempting to compile and run the above programs?

Question 2

class MCZ28 {
  public static void main (String[] args) {
    char a = '\b';  // 1
    char b = '\d';  // 2
    char c = '\f';  // 3
    char d = '\t';  // 4
    char e = '\"';  // 5
}}

A compile-time error is generated at which line?

Question 3

// Class A is declared in a file named A.java.
package com.dan.chisholm;
public class A {
   public void m1() {System.out.print("A.m1, ");}
   protected void m2() {System.out.print("A.m2, ");}
   private void m3() {System.out.print("A.m3, ");}
   void m4() {System.out.print("A.m4, ");}
}
// Class C is declared in a file named C.java.
package com.dan.chisholm.other;
import com.dan.chisholm.A;
public class C extends A {
  public static void main(String[] args) {
    C c = new C();
    c.m1();  // 1
    c.m2();  // 2
    c.m3();  // 3
    c.m4();  // 4
}}

What is the result of attempting to compile and run the program?

Question 4

Which of the following are modifiers that can be applied to an interface that is a member of a directly enclosing interface?

Question 5

class JJF3 {
  public static void main(String args[]) {
    System.out.print(Integer.toBinaryString(Byte.MAX_VALUE)+",");
    System.out.print(Integer.toOctalString(Byte.MAX_VALUE)+",");
    System.out.print(Integer.toString(Byte.MAX_VALUE)+",");
    System.out.print(Integer.toHexString(Byte.MAX_VALUE));
}}

What is the result of attempting to compile and run the program?

Question 6

class EBH203 {
  static boolean a, b, c;
  public static void main (String[] args) {
    boolean x = a || (b = true) && (c = true);
    System.out.print(a + "," + b + "," + c);
}}

What is the result of attempting to compile and run the program?

Question 7

class GFC102 {
  public static void main(String[] args) {
    byte b1 = -129;    // 1
    byte b2 = 127;     // 2
    short s1 = -32768; // 3
    short s2 = 32768;  // 4
    char c1 = -1;      // 5
    char c2 = 65535;   // 6
}}

Compile-time errors are generated at which lines?

Question 8

class GFC403 {
  private static int x=1;
  static void m1(int i) {x++; i++;}
  public static void main (String[] args) {
    int y=3; m1(y);
    System.out.println(x + "," + y);
}}

What is the result of attempting to compile and run the program?

Question 9

A class can not be called "tightly encapsulated" unless which of the following is true?

Question 10

Which of the following methods are deprecated members of the Thread class?

Question 11

class SRC104 {
  public static void main (String[] args) {
    System.out.print(Math.round(Float.NaN));
}}

What is the result of attempting to compile and run the program?

Question 12

class D {
  public static void main (String args[]) {
    Byte a = new Byte("1");
    byte b = a.byteValue();
    short c = a.shortValue();
    char d = a.charValue();
    int e = a.intValue();
    long f = a.longValue();
    float g = a.floatValue();
    double h = a.doubleValue();
    System.out.print(b+c+d+e+f+g+h);
}}

What is the result of attempting to compile and run the program?

Question 13

class A {
  public static void main (String args[]) {
    Integer i1 = new Integer(1);
    Integer i2 = new Integer(i1);
    System.out.print(i1.equals(i2));
}}

What is the result of attempting to compile and run the program?

Question 14

class C {
  public static void main (String args[]) {
    Long a = new Long(1);
    byte b = a.byteValue();
    short s = a.shortValue();
    char c = a.charValue();
    int d = a.intValue();
    long e = a.longValue();
    float f = a.floatValue();
    double g = a.doubleValue();
    System.out.print(b+s+c+d+e+f+g);
}}

What is the result of attempting to compile and run the program?

Question 15

class B {
  public static void main (String args[]) {
    Double a = new Double(0xFFFF);
    byte b = a.byteValue();
    short c = a.shortValue();
    int e = a.intValue();
    long f = a.longValue();
    float g = a.floatValue();
    double h = a.doubleValue();
    System.out.print(b+","+c+","+ (e+f+g+h == 4 * 0xFFFF));
}}

What is the result of attempting to compile and run the program?

Question 16

class GFM13 {
  static byte a; static short b; static char c;
  static int d; static long e; static String s;
  public static void main(String[] args) {
    System.out.println(a+b+c+d+e+s);
}}

What is the result of attempting to compile and run the program?

Question 17

class Maroon {
  public static void main (String[] args) {
    int a = 1;    // 1
    short b = 1;  // 2
    long c = 1;   // 3
    a = c + a;    // 4
    c = b + a;    // 5
}}

A compile-time error is generated at which line?

Question 18

interface I1 {}
interface I2 {}
class Base implements I1 {}
class Sub extends Base implements I2 {}
class Yellow {
  public static void main(String args[]) {
    Base base = new Sub();  // 1
    I1 i1 = base;           // 2
    Sub sub = (Sub)base;    // 3
    I2 i2 = (Sub)base;      // 4
}}

A compile-time error is generated at which line?

Question 19

import java.io.Serializable;
class Blue {
  public static void main (String args[]) {
    int[] i = {1,2,3};   // 1
    Serializable s = i;  // 2
    i = (int [])s;       // 3
}}

What is the result of attempting to compile and run the program?

Question 20

class GFC217 {
  static String m(int i) {return "int";}
  static String m(float i) {return "float";}
  public static void main (String[] args) {
    long a1 = 1; double b1 = 2;
    System.out.print(m(a1)+","+ m(b1));
}}

What is the result of attempting to compile and run the program?

Question 21

class E {
  void printS1(){System.out.print("E.printS1 ");}
  static void printS2() {System.out.print("E.printS2");}
}
class F extends E {
  void printS1(){System.out.print("F.printS1 ");}
  static void printS2() {System.out.print("F.printS2");}
  public static void main (String args[]) {
    E x = new F(); x.printS1(); x.printS2();
}}

What is the result of attempting to compile and run the program?

Question 22

class C {
  private static String s1 = "s1";
  String s2 = "s2";
  C() {m1("s5","s6");}
  void m1(final String s5, String s6) {
    final String s3 = "s3"; String s4 = "s4";
    class Z {Z() {System.out.print(???);}}
    new Z();
  }
  public static void main(String args[]) {new C();}
}

Which variable names can be substituted for ??? without causing a compile-time error?

Question 23

class A {void m1(A a) {System.out.print("A");}}
class B extends A {void m1(B b) {System.out.print("B");}}
class C extends B {void m1(C c) {System.out.print("C");}}
class D {
  public static void main(String[] args) {
    A c1 = new C(); B c2 = new C();
    C c3 = new C(); C c4 = new C();
    c4.m1(c1); c4.m1(c2); c4.m1(c3);
}}

What is the result of attempting to compile and run the program?

Question 24

class MWC104 {
  public static void main (String[] args) {
    char[] c = {'a','b','c','d'};
    String s1 = new String(c);
    boolean b = true;
    for (int i = 0; i < s1.length; i++) {
      b &= (c[i] == s1.charAt(i));
    }
    System.out.print(b);
}}

What is the result of attempting to compile and run the program?

Question 25

class MWC202 {
  public static void main (String[] args) {
    StringBuffer sb1 = new StringBuffer("ABC");
    StringBuffer sb2 = new StringBuffer("ABC");
    System.out.print((sb1==sb2)+","+sb1.equals(sb2));
}}

What is the result of attempting to compile and run the program?

Question 26

Which of these lists contains at least one word that is not a Java keyword?

Question 27

class EBH103 {
  public static void main (String[] args) {
    byte a = 1, b = 2, c, d, e;
    c = (byte)a++;
    d = (byte)++b;
    e = (byte)a + b;
    System.out.print(c + d + e);
}}

What is the result of attempting to compile and run the above program?

Question 28

class GFC304 {
  static void m1(int[] i1, int[] i2) {
    int[] i3 = i1; i1 = i2; i2 = i3;
  }
  public static void main (String[] args) {
    int[] i1 = {1}, i2 = {3}; m1(i1, i2);
    System.out.print(i1[0] + "," + i2[0]);
}}

What is the result of attempting to compile and run the program?

Question 29

class EBH003 {
  static int m(int i) {
    System.out.print(i + ", ");
    return i;
  }
  public static void main(String s[]) {
    m(m(~1) + m(1|2) + m(1&2) + m(1^3) + m(1<<1));
}}

What is the result of attempting to compile and run the program?