1z0-809 Practice Test

Given:

What is the result?

A.

The program prints nothing

B.

A NullPointerException is thrown at runtime.

C.

A StringIndexOutOfBoundsException is thrown at runtime.

D.

AnArrayIndexOutOfBoundsException is thrown at runtime

Given:
public class Foo<K, V> {
private K key;
private V value;
public Foo (K key, V value) (this.key = key; this value = value;)
public static <T> Foo<T, T> twice (T value) (return new Foo<T, T> (value, value); )
public K getKey () (return key;)
public V getValue () (return value;)
}
Which option fails?

A.

Foo<String, Integer> mark = new Foo<String, Integer> (“Steve”, 100);

B.

Foo<String, String> pair = Foo.<String>twice (“Hello World!”);

C.

Foo<?, ?> percentage = new Foo <> (97, 32);

D.

Foo<String, String> grade = new Foo <> (“John”, “A”);

Given the code fragments:

What is the result?

A.

Super
Sub
Sub

B.

Contract
Contract
Super

C.

Compilation fails at line n1

D.

Compilation fails at line n2

Given the content of /resourses/Message.properties:
welcome1=”Good day!”
and given the code fragment:
Properties prop = new Properties ();
FileInputStream fis = new FileInputStream (“/resources/Message.properties”);
prop.load(fis);
System.out.println(prop.getProperty(“welcome1”));
System.out.println(prop.getProperty(“welcome2”, “Test”));//line n1
System.out.println(prop.getProperty(“welcome3”));
What is the result?

A.

Good day!
Test
followed by an Exception stack trace

B.

Good day!
followed by an Exception stack trace

C.

Good day!
Test
null

D.

A compilation error occurs at line n1.

Given:
Class A { }
Class B { }
Interface X { }
Interface Y { }
Which two definitions of class C are valid?

A.

Class C extends A implements X { }

B.

Class C implements Y extends B { }

C.

Class C extends A, B { }

D.

Class C implements X, Y extends B { }

E.

Class C extends B implements X, Y { }