Java written test questions and answers (basic difficulty written test questions)

#1. There is a java application whose main class name is al, so what can the source file that saves it be? ()

# Al.java (Recommended Learning: Java Programmers Interview Questions )

## B.al.class

## C. al

D. All correct

Answer: A

Analysis: .class is the parsing file of java

2 .Java classes can be used as ()

A Type definition mechanism

B. Data encapsulation mechanism

C. Type definition mechanism and data encapsulation mechanism

D. None of the above are correct

Answer: C

3. When calling a method, is it okay to make the method change the value of the actual parameter? ()

A Use basic data types as parameters

B. Use objects as parameters

C.A and B are both correct

D.A and B None of them are correct

Answer: B

Analysis: Basic data types cannot change the value of actual parameters

4. The Java language has many advantages and Features, which reflect the parallel mechanism of Java programs. ()

A Security

B. Multi-linear

C. Cross-platform

D. Portable

Answer: Portable

5. The error in the following description of the constructor is ()

A The return type of the constructor can only be void

B. The constructor is a special function of the class, and its method name must be the same as the class name

C. The main function of the constructor is to complete the initialization of the object of the class

D. Generally when creating a new object, the system will automatically call the constructor

Answer: A

Analysis: The name of the constructor is the same as the name of the class and cannot be specified Return type.

6. If you need to define a class field or class method, which modifier should be used? ()

A static

B.package

C.private

D.public

Answer ：A

7. What is the output after executing the following code ()

package cn.wuliaokankan;
public class Test {
    public static void main(String[] args) {
        outer: for (int i = 0; i < 3; i++)
        inner: for (int j = 0; j < 2; j++) {
            if (j == 1)
            continue outer;
            System.out.println(j + " and " + i);
        }
    }
}

A.

0 and 0

0 and 1

0 and 2

B.

1 and 0

1 and 1

1 and 2

C.

2 and 0

2 and 1

2 and 2

Answer: A

8. Given the following code, how to make member variable m directly accessed by function fun()()

package cn.wuliaokankan;
public class Test {
    private int m;
    public static void fun() {
        // some code…
    }
}

A. Change private int m to protected int m

B. Change private int m to public int m

C. Change private int m to static int m

D. Change private int m to int m

Answer: C

9. Which of the following functions are overloaded functions () of public void example(){….}

A public void example(int m){…}

B.public int example(int m){…}

C.public void example2(){…}

D.public int example(int m, float f){…}

Answer: ABD

10.Execute the following code What will be printed?

Parent class:

package cn.wuliaokankan;
public class FatherClass {
    public FatherClass() {
        System.out.println("FatherClassCreate");
    }
}

Subclass:

package cn.wuliaokankan;
import cn.wuliaokankan.FatherClass;
public class ChildClass extends FatherClass {
    public ChildClass() {
        System.out.println("ChildClass Create");
    }
    public static void main(String[] args) {
        FatherClass fc = new FatherClass();
        ChildClass cc = new ChildClass();
    }
}

Execution: C:\>java cn .wuliaokankan.ChildClass

Output result:?

Answer:

FatherClassCreate
FatherClassCreate
ChildClass Create

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