Dan Chisholm's
Java Programmer Certification Mock Exam

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Question 1

public class Basics {}   // 1
public class Basics2 {}  // 2
public class Basics3 {}  // 3
public class Basics4 {}  // 4

Suppose these are top-level class declarations and not nested class declarations; and suppose that all of the declarations are contained in one file named Basics.java. A compile-time error is not generated at which line?

Question 2

Which of these words belongs to the set of Java keywords?

Question 3

class MCZ30 {
  public static void main (String[] args) {
    char a = '\t';  // 1
    char b = '\\';  // 2
    char c = '\?';  // 3
    char d = '\"';  // 4
    char e = '\'';  // 5  
}}

A compile-time error is generated at which line?

Question 4

Which of the following modifiers can be applied to a local class?

Question 5

class Level1Exception extends Exception {}
class Level2Exception extends Level1Exception {}
class Level3Exception extends Level2Exception {}
class Purple {
  public static void main(String args[]) {
    int a,b,c,d,f,g,x;
    a = b = c = d = f = g = 0;
    x = 3;
    try {
      try {
        switch (x) {
          case 1: throw new Level1Exception();
          case 2: throw new Level2Exception();
          case 3: throw new Level3Exception();
      } a++; }
      catch (Level2Exception e) {b++;}
      finally {c++;}
    }
    catch (Level1Exception e) { d++;}
    catch (Exception e) {f++;}
    finally {g++;}
    System.out.print(a+","+b+","+c+","+d+","+f+","+g);
}}

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

Question 6

Which of the following is a modifier that can be applied to an interface that is a member of a directly enclosing class or interface?

Question 7

class JJF5 {
  public static void main(String args[]) {
    System.out.print(Integer.toHexString(Integer.MIN_VALUE)+",");
    System.out.print(Integer.toHexString(Integer.MAX_VALUE));
}}

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

Question 8

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

Question 9

A timeout argument can be passed to which of the following methods?

Question 10

Which of these methods modify the contents of the String instance on which it is invoked?

Question 11

class SRC106 {
  public static void main(String[] args) {
    double d1 = Math.floor(0.5);
    double d2 = Math.floor(1.5);
    System.out.print(d1 + "," + d2);
}}

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

Question 12

class MWC204 {
  static void m1(StringBuffer s1) {
    s1 = s1.append("B"); System.out.print(s1);
  }
  static void m2(StringBuffer s1) {
    s1.append("C"); System.out.print(s1);
  }
  public static void main(String[] s) {
    StringBuffer s1 = new StringBuffer("A");
    m1(s1); m2(s1);
    System.out.print(s1);
}}

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

Question 13

class E {
  public static void main (String[] args) {
    Byte b1 = new Byte("1"), b2 = new Byte("1");
    int a = b1.hashCode(), b = b2.hashCode();
    System.out.print((b1.equals(b2))+","+(a==b));
}}

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

Question 14

class E {
  static String m(int i) {return "int primitive";}
  static String m(Integer i) {return "Integer instance";}
  static String m(double i) {return "double primitive";}
  static String m(Double i) {return "Double instance";}
  static String m(String i) {return "String instance";}
  public static void main (String[] args) {
    System.out.print(m(Integer.parseInt("1")));
}}

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

Question 15

class F {
  static String m(long i) {return "long";}
  static String m(Long i) {return "Long";}
  static String m(double i) {return "double";}
  static String m(Double i) {return "Double";}
  static String m(String i) {return "String";}
  public static void main (String[] args) {
    System.out.print(m(Long.parseLong("1L")));
}}

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

Question 16

class JMM104 {
  public static void main (String args[]) {
    char c = 'b';
    switch(c) {
      case 'a': System.out.print("1");
      case 'b': System.out.print("2");
      case 'c': System.out.print("3");
      default:  System.out.print("4");
}}}

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

Question 17

class C {
  String m1(int i) {
    switch (i) {
      case 0: return "A";
      case 1: return "B";
      case 2: return "C";
      default: throw new AssertionError();
  }}
  public static void main(String[] args) {
    C c = new C();
    for (int i = 0; i < 4; i++) {
      System.out.print(c.m1(i));
}}}

Which statements are true?

Question 18

class I {
  private I other;
  public void other(I i) {other = i;}
}
class J {
  private void m1() {
    I i1 = new I(), i2 = new I();
    I i3 = new I(), i4 = new I();
    i1.other(i3); i2.other(i1);
    i3.other(i2); i4.other(i4);
  }
  public static void main (String[] args) {
    new J().m1();
}}

Which object is not eligible for garbage collection after method m1 returns?

Question 19

class GFM15 {
  static int a; static float b; static double c;
  static boolean d; static String s;
  public static void main(String[] args) {
    System.out.println(a+","+b+","+c+","+d+","+s);
}}

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

Question 20

class EBH007{
  public static void main (String[] s) {
    byte b = 5; System.out.println(b<<33);
}}

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

Question 21

class Sienna {
  static double a; static float b; static int c; static char d;
  public static void main(String[] args) {
    a = b = c = d = 'a';
    System.out.println(a+b+c+d == 4 * 'a');
}}

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

Question 22

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

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

Question 23

class White {
  public static void main(String args[]) {
    int[] i = {1,2,3,4,5};     // 1
    long[] l1 = new long[5];   // 2
    long []l2 = l1;            // 3
    long l3[] = (long[])i;     // 4
    long l4[] = new long[5];   // 5
    l4[1] = i[1];              // 6
}}

A compile-time error is generated at which line?

Question 24

class GFC200 {}
class GFC201 {
  static void m(Object x) {System.out.print("Object");}
  static void m(String x) {System.out.print("String");}
  static void m(GFC200 x) {System.out.print("GFC200");}
  public static void main(String[] args) {m(null);}
}

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

Question 25

class R {
  private void printS1(){System.out.print("R.printS1 ");}
  protected void printS2() {System.out.print("R.printS2 ");}
  protected void printS1S2(){printS1();printS2();}
}
class S extends R {
  private void printS1(){System.out.print("S.printS1 ");}
  protected void printS2(){System.out.print("S.printS2 ");}
  public static void main(String[] args) {
    new S().printS1S2();
}}

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

Question 26

class E {
  E() {System.out.print("E");}
  static class Z {Z(){System.out.print("Z");}}
  public static void main(String args[]) {
   new E.Z();
}}

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

Question 27

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 a1 = new A(); A b1 = new B(); A c1 = new C(); C c4 = new C();
    a1.m1(c4); b1.m1(c4); c1.m1(c4);
}}

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

Question 28

class EBH105 {
  static int m(int i) {System.out.print(i + ","); return 0;}
  public static void main (String[] args) {
    int i = 0; i = i++ + m(i); System.out.print(i);
}}

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

Question 29

class GFC306 {
  static int[] i1 = {1}, i2 = {3};
  static void m1(int[] i1) {
    int[] i3 = i1; i1 = i2; i2 = i3;
  }
  public static void main (String[] args) {
    m1(i1);
    System.out.print(i1[0] + "," + i2[0]);
}}

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