int index = 1;
String test = new String;
String foo = test[index];
What is the result?()
A. Foo has the value “”
B. Foo has the value null
C. An exception is thrown
D. The code will not compile
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public class Test {
public static void main (Stringargs) {
String foo = args[1];
String bar = args;
String baz = args;
System.out.printIn(“baz = ” + baz);
}
}
And the output: Baz = 2
Which command line invocation will produce the output?()
A. Java Test 2222
B. Java Test 1 2 3 4
C. Java Test 4 2 4 2
D. Java Test 4 3 2 1
package foo;
import java.util.Vector;
private class MyVector extends Vector {
int i = 1;
public MyVector() {
i = 2;
}
}
public class MyNewVector extends MyVector {
public MyNewVector () {
i = 4;
}
public static void main (String args ) {
MyVector v = new MyNewVector();
}
}
The file MyNewVector.java is shown in the exhibit. What is the result?()
A. Compilation will succeed.
B. Compilation will fail at line 5.
C. Compilation will fail at line 6.
D. Compilation will fail at line 14.
E. Compilation will fail at line 17.
A. false
B. default
C. _object
D. a-class
A. New BufferedInputStream(“in.txt”);
B. New BufferedInputStream(new File(“in.txt”));
C. New BufferedInputStream(Writer(“in.txt”));
D. New BufferedInputStream(new Writer(“in.txt”));
E. New BufferedInputStream(new InputStream(“in.txt”));
F. New BufferedInputStream(new FileInputStream(“in.txt”));
A. OutputStream out=new FileOutputStream(“file.txt”);
B. OutputStream out=new FileOutputStream(“file.txt”, “append”);
C. FileOutputStream out=new FileOutputStream(“file.txt”, true);
D. FileOutputStream out=new FileOutputStream(new file(“file.txt”));
E. OutputStream out=new FileOutputStream(new File(“file.txt”)true);
A. InputStream in=new FileReader(“file.txt”);
B. InputStream in=new FileInputStream(“file.txt”);
C. InputStream in=new InputStreamFileReader (“file.txt”, “read”);
D. FileInputStream in=new FileReader(new File(“file.txt”));
E. FileInputStream in=new FileInputStream(new File(“file.txt”));
A. Boolean exists=Directory.exists (“prefs”);
B. Boolean exists=(new File(“prefs”)).isDir();
C. Boolean exists=(new Directory(“prefs”)).exists();
D. Boolean exists=(new File(“prefs”)).isDirectory();
E. Boolean exists=true; Try{ Directory d = new Directory(“prefs”); } catch (FileNotFoundException e) { exists = false; }
class super {
public int getLength() {return 4;}
}
public class Sub extends Super {
public long getLength() {return 5;}
public static void main (Stringargs) {
super sooper = new Super ();
Sub sub = new Sub();
System.out.printIn(
sooper.getLength()+ “,” + sub.getLength() };
}
What is the output?()
A. 4, 4
B. 4, 5
C. 5, 4
D. 5, 5
E. The code will not compile.
A. The default constructor initializes method variables.
B. The compiler always creates a default constructor for every class.
C. The default constructor invokes the no-parameter constructor of the superclass.
D. The default constructor initializes the instance variables declared in the class.
E. When a class has only constructors with parameters, the compiler does not create a default constructor.
public class ArrayTest {
public static void main (Stringargs) {
float f1, f2;
f1 = new float [10];
f2 = f1;
System.out.printIn (“f2[0]=” + f2[0]);
}
}
What is the result?()
A. It prints f2[0] = 0.0
B. It prints f2[0] = NaN
C. An error at line 5 causes compile to fail.
D. An error at line 6 causes compile to fail.
E. An error at line 6 causes an exception at runtime.
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