1Z0-853 by Oracle Actual Free Exam Q&As

Question 1

Given:
1.interface A { public void aMethod(); }
2.interface B { public void bMethod(); }
3.interface C extends A,B { public void cMethod(); }
4.class D implements B {
5.public void bMethod(){}
6.}
7.class E extends D implements C {
8.public void aMethod(){}
9.public void bMethod(){}
10.
public void cMethod(){}
11.
}
What is the result?

A. If you define D e = (D)(new E()), then e.bMethod() invokes the version of bMethod() defined in Line 9. B. Compilation fails because of an error in line 3. C. Compilation fails because of an error in line 7. D. Compilation fails because of an error in line 9. E. If you define D e = new E(), then e.bMethod() invokes the version of bMethod() defined in Line 5. F. If you define D e = (D)(new E()), then e.bMethod() invokes the version of bMethod() defined in Line 5.

Discussion 0

Correct Answer: A Vote an answer

Question 2

Given:
11.
public class Key {
12.
private long id1;
13.
private long id2;
14.
15.
// class Key methods
16.
}
A programmer is developing a class Key, that will be used as a key in a standard java.util.HashMap.
Which two methods should be overridden to assure that Key works correctly as a key? (Choose two.)

A. public int hashCode() B. public boolean equals(Key k) C. public int compareTo(Object o) D. public boolean equals(Object o) E. public boolean compareTo(Key k)

Discussion 0

Correct Answer: A,D Vote an answer

Question 3

Given this method in a class:
21.
public String toString() {
22.
StringBuffer buffer = new StringBuffer();
23.
buffer.append('<');
24.
buffer.append(this.name);
25.
buffer.append('>');
26.
return buffer.toString();
27.
}
Which statement is true?

A. This code will perform well and converting the code to use StringBuilder will not enhance the performance. B. This code will perform poorly. For better performance, the code should be rewritten: return "<" + this.name + ">"; C. This code is NOT thread-safe. D. The programmer can replace StringBuffer with StringBuilder with no other changes.

Discussion 0

Correct Answer: D Vote an answer

Question 4

Given:
1.public class Plant {
2.private String name;
3.public Plant(String name) { this.name = name; }
4.public String getName() { return name; }
5.}
1.public class Tree extends Plant {
2.public void growFruit() { }
3.public void dropLeaves() { }
4.}
Which statement is true?

A. The code will compile without changes. B. The code will compile if public Plant() { Plant("fern"); } is added to the Plant class. C. The code will compile if public Plant() { Tree(); } is added to the Plant class. D. The code will compile if public Tree() { Plant(); } is added to the Tree class. E. The code will compile if public Plant() { this("fern"); } is added to the Plant class.

Discussion 0

Correct Answer: E Vote an answer

Question 5

Given:
1.package geometry;
2.public class Hypotenuse {
3.public InnerTriangle it = new InnerTriangle();
4.class InnerTriangle {
5.public int base;
6.public int height;
7.}
8.}
Which statement is true about the class of an object that can reference the variable base?

A. No class has access to base. B. The class must belong to the geometry package. C. It can be any class. D. The class must be a subclass of the class Hypotenuse.

Discussion 0

Correct Answer: B Vote an answer

Question 6

Click the Exhibit button. Given:
34.
Test t = new Test();
35.
t.method(5);
What is the output from line 5 of the Test class?

Discussion 0

Correct Answer: D Vote an answer

Question 7

Click the Exhibit button. What is the result?

A. The code may run with output "0 2 4 6". B. An exception is thrown at runtime. C. The code may run with output "2 0 6 4". D. The code may run with output "0 6". E. The code may run with no output. F. The code will deadlock.

Discussion 0

Correct Answer: A Vote an answer

Question 8

Given:
10. interface Jumper { public void jump(); } ...
20. class Animal {} ...
30.
class Dog extends Animal {
31.
Tail tail;
32.
} ...
40.
class Beagle extends Dog implements Jumper{
41.
public void jump() {}
42.
} ...
50.
class Cat implements Jumper{
51.
public void jump() {}
52.
}
Which three are true? (Choose three.)

A. Beagle has-a Tail B. Cat is-a Animal C. Cat has-a Animal D. Beagle has-a Jumper E. Dog is-a Animal F. Dog is-a Jumper G. Cat is-a Jumper

Discussion 0

Correct Answer: A,E,G Vote an answer

Question 9

Given:
11.
public class Test {
12.
public static void main(String [] args) {
13.
int x = 5;
14.
boolean b1 = true;
15.
boolean b2 = false;
16.
17.
if ((x == 4) && !b2 )
18.
System.out.print("1 ");
19.
System.out.print("2 ");
20.
if ((b2 = true) && b1 )
21.
System.out.print("3 ");
22.
}
23.
}
What is the result?

A. 3 B. An exception is thrown at runtime. C. 1 2 D. 2 3 E. Compilation fails. F. 2 G. 1 2 3

Discussion 0

Correct Answer: D Vote an answer

Question 10

Given:
11.
static void test() {
12.
try {
13.
String x = null;
14.
System.out.print(x.toString() + " ");
15.
}
16.
finally { System.out.print("finally "); }
17.
}
18.
public static void main(String[] args) {
19.
try { test(); }
20.
catch (Exception ex) { System.out.print("exception "); }
21.
}
What is the result?

A. Compilation fails. B. null finally C. finally exception D. null E. finally

Discussion 0

Correct Answer: C Vote an answer

Question 11

Given:
10.
interface Foo { int bar(); }
11.
public class Sprite {
12.
public int fubar( Foo foo ) { return foo.bar(); }
13.
public void testFoo() {
14.
fubar(
15.
// insert code here
16.
);
17.
}
18.
}
Which code, inserted at line 15, allows the class Sprite to compile?

A. new Foo { public int bar() { return 1; } B. Foo { public int bar() { return 1; } C. new Foo() { public int bar() { return 1; } D. new class Foo { public int bar() { return 1; }

Discussion 0

Correct Answer: C Vote an answer

Oracle Java Standard Edition 5 Programmer Certified Professional - 1Z0-853 Exam Practice Test