Java tests

Question 1: You are planning to do an indexed search in a list of objects. Which of the two Java collections should you use:

1. ArrayList
2. LinkedList

   
Question 2: Inner classes can be defined within methods.

1. False
2. True

Question 3: The default statement of a switch is always executed.

1. False
2. True

Question 4: What is the size of a Char?

1. 16 bits
2. 4 bits
3. 7 bits
4. 8 bits

Question 5: The following code will result in:

class A {
  public static void main(String [] args) {
    B b = new A();
  }
}
class B extends A {
}

1. Compile error
2. No error
3. Runtime Exception

Question 6: Can you compare a boolean to an integer?   

Question 7: Can you call one constructor from another if a class has multiple constructors?
Answer: yes:
public class Foo
{
    private int x;

    public Foo()
    {
        this(1);
    }

    public Foo(int x)
    {
        this.x = x;
    }
}

Question 8: For how long will the thread wait after calling wait(1000)?

1. 1 second
2. 1000 seconds
3. until it receives notify() or notifyAll() calls
4. up to 1 second

Question 9: With the following code what happens when you do if (a==b)? False!
Integer a = new Integer(2);
Integer b = new Integer(2);

1. Compiler error
2. False
3. Runtime Exception
4. True

Question 10: A class cannot be declared: ?????
Default
Private
Static

Question 11: Can you write a Java class that could be used both as an applet as well as an application?

Question 12: The following code will result in:
class A {
  int b = 1;
  public static void main(String [] args) {
    System.out.println("b is " + b);
  }
}

1. Compilation error
2. Output of b is 1
3. Runtime Error
4. Runtime Exception

Question 13: If the code in the try block attempts to open an non-existing file
Will you ever see File not found printed out?

try {
  // ... some code ...
} catch (IOException e) {
  System.out.println("IO Error");
} catch (FileNotFoundException e) {
  System.out.println("File not found");
}

1. No
2. Will not compile
3. Yes 

Question 14: java assert

Question 15: Following code will result in:
int a = 9/0;

1. Compilation error: DivideByZeroException
2. Compilation error: Divisions must be in a try block.
3. No Error: a is NaN
4. Runtime Exception

Question 16: What will happen?
public class Static
{
      static
      {
            int x = 5;
      }
      static int x,y;
      public static void main(String args[])
      {
            x--; myMethod();
            System.out.println(x + y + ++x);
      }
      public static void myMethod()
      {
             y = x++ + ++x;
      }
}

Question 17: Can an inner class declared inside of a method access local variables of this method?
No
Only final variables
Only variables of primitive types
Yes, always

Question 18: A class can be transient

1. Primitive datatypes are allocated on a stack?
2. Java only allocates primitive data types like int and double and object references on the stack. All objects are allocated on the heap.

Question 19: Which method is not member of Object?

1. clone
2. compare
3. equals
4. finalize
5. notify

Question 20: Which directory should you add to the CLASSPATH environment variable?
You want to access the class MyClass from package com.my.somestuff
The file is here:
C:\javaworks\project1\com\my\somestuff\MyClass.java

1. C:\javaworks
2. C:\javaworks\project1
3. C:\javaworks\project1\com\my
4. C:\javaworks\project1\com\my\somestuff