Certified Java Programmer Mock Exam

Question 1

class SRC109 {
  public static void main (String[] args) {
    short x3 = 0; short x4 = 1;
    short b1 = Math.min(x3,x4); // 1
    int c1 = Math.min(0,1);     // 2
    long d1 = Math.min(0L,+1L); // 3
    System.out.print(b1+","+c1+","+d1);
}}

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

Question 2

class C {
  public static void main (String args[]) {
    String s1 = "1", s2 = "2";
    Byte b1 = Byte.parseByte(s1);
    Byte b2 = Byte.parseByte(s2);
    System.out.print(b1.byteValue() + b2.byteValue());
}}

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

Question 3

class A {
  public static void main (String[] args) {
    String s = "11";
    int i1 = Integer.parseInt(s);
    System.out.print(new Integer(i1).equals(new Integer(i1)) + ",");
    System.out.print(new Integer(i1).equals(new Integer(s))  + ",");
    System.out.print(new Integer(i1) == new Integer(i1));
}}

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

Question 4

Which of the method invocation expressions would produce a run-time error?

Question 5

Which method of the java.lang.Double class returns an instance of type Double?

Question 6

class MWC107 {
  public static void main(String[] s) {
    String s1 = "A", s2 = " B ", s3 = "C";
    s2.trim(); s3.concat("D");
    System.out.print(s1 + s2 + s3);
}}

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

Question 7

class SRC110 {
  public static void main (String[] args) {
    byte x1 = 0; byte x2 = 1;
    byte a1 = Math.min(x1,x2);  // 1
    int c1 = Math.min(0,1);     // 2
    long d1 = Math.min(0L,+1L); // 3
    System.out.print(a1+","+c1+","+d1);
}}

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

Question 8

class B {
  public static void main (String[] args) {
    byte b1 = 11;
    System.out.print(new Integer(b1).equals(new Integer(b1)) + ",");
    System.out.print(new Integer(b1).equals(new Short(b1)) + ",");
    System.out.print(new Integer(b1).equals(new Byte(b1)));
}}

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

Question 9

Which of the method invocation expressions would produce a run-time error?

Question 10

Which methods of the java.lang.Double class declare a parameter of type String?

Question 11

class MWC108 {
  public static void main(String[] s) {
    String s1 = "A", s2 = " B ", s3 = "C";
    s2.trim(); s3.append("D");
    System.out.print(s1 + s2 + s3);
}}

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

Question 12

class SRC111 {
  static String m(byte i) {return "byte";}
  static String m(short i) {return "short";}
  static String m(char i) {return "char";}
  static String m(int i) {return "int";}
  static String m(double i) {return "double";}
  public static void main (String[] args) {
    byte b = 0; short s = 0; char c = 0;
    System.out.print(m(Math.min(b,b))+",");
    System.out.print(m(Math.min(s,s))+",");
    System.out.print(m(Math.min(c,c)));
}}

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

Question 13

Which of the following methods of the java.lang.Integer class returns a primitive int type?

Question 14

Which methods of the java.lang.Double class declare a NumberFormatException in the throws clause?

Question 15

class SRC112 {
  static String m(byte i) {return "byte";}
  static String m(int i) {return "int";}
  static String m(long i) {return "long";}
  static String m(double i) {return "double";}
  public static void main (String[] args) {
    byte b = 0;
    System.out.print(m(Math.min(b,b))+",");
    System.out.print(m(Math.min(b,1))+",");
    System.out.print(m(Math.min(b,1L)));
}}

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

Question 16

class F {
  public static void main (String[] args) {
    Integer i1 = new Integer("1");
    Integer i2 = new Integer("1");
    int h1 = i1.hashCode(), h2 = i2.hashCode();
    StringBuffer sb1 = new StringBuffer("1");
    StringBuffer sb2 = new StringBuffer("1");
    int h3 = sb1.hashCode(), h4 = sb2.hashCode();
    System.out.print((h1==h2)+","+(h3==h4));
}}

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

Question 17

class F {
  public static void main (String args[]) {
    Double d1 = new Double("0x10");         // 1
    double d2 = Double.parseDouble("0x10"); // 2
    Double d3 = Double.valueOf("0x10");     // 3
    System.out.print(d1+","+d2+","+d3);
}}

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

Question 18

class MWC110 {
  static void m1(String s1, String s2) {
    s1.insert(1,"D"); s1 = s1 + s2;
  }
  public static void main(String[] s) {
    String s1 = "A", s2 = "B";
    m1(s1,s2);
    System.out.print(s1 + s2);
}}

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

Question 19

class MWC109 {
  public static void main(String args[]) {
    String a = "A", b = "B", c = a+b, d = a+b;
    System.out.print(((a+b)==(a+b)) + ",");
    System.out.print((c==d) + ",");
    System.out.print(c.equals(d));
}}

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