Core Java Quiz on Strings – Make Sure You Know the Essentials

Which of the following is not valid in case of Java String?

Which of the following correctly describes the reason for String to be final or immutable?

Which of the following is the correct difference between String and StringBuffer in Java?

Which of the following is the correct difference in String on C and Java?

What does the following instruction suppose to do?
str.replaceAll(Character.toString(‘c’), “”);

Which of the following methods is used to compare two Strings in a Java program? And if the Strings don’t match, then it returns a non-zero value.

Which of the following statement would correctly convert String to byte array and vice versa?

Which of the following correctly defines String pool in Java?

What does the intern() method do in Java?

Why Char array is preferred over String for storing password?

What would be the results of the last two statements?

String x = "techbeamers";
String y = new String(new char[] { 't', 'e', 'c', 'h', 'b', 'e', 'a', 'm', 'e', 'r', 's' });

System.out.println(x == y);
System.out.println(x.equals(y));

Which of the following correctly describes the difference in the way the two “==” and equals() work in Java?

Which statement is valid for the fact mentioned below?
Immutable objects are naturally thread-safe.

Which statement is valid for the fact mentioned below?
If we change the value of an existing String object then it creates a new object instead of updating the existing object.

Which statement is valid for the fact mentioned below?
If you plan to modify a String, then better use StringBuffer. StringBuffer updates the existing objects value, rather creating a new object.

Is it possible to use String in the switch statement?

Which of the following correctly describes the result of the below line of code in Java?

String[] strArray = aString.split("\\s+");

What is the output of the Java statement given below?

System.out.println(Integer.parseInt("10"));

What is the initial capacity of the string builder in the example given below?

StringBuilder sb = new StringBuilder("top 30 Java String interview questions.");

What is the output value and the length of the string returned by the below expression?

"Was it a bee or a bat I saw?".substring(9, 12);

What is the value displayed by the expression Java.length()?

String Java = "Are you a Java expert? Yes, you are.";

What is the value returned by the method call Java.charAt(9)?

String Java = "Are you a Java expert? Yes, you are.";

Which of the following expression would return the letter “?” from the string referred by JavaStr?

String JavaStr = "Are you a Java expert? Yes, you are.";

Which of the following statement mentions the right ways to concatenate the two strings?

Which of the following correctly defines the toString() method in Java?

State whether the following statement is true or false?
String is not a keyword instead a derived type in java. String is a final class in java.lang package.

Which of the following is a final class in Java?

Which of the following is a difference between StringBuffer and StringBuilder class?

How many objects will be created in the following code and where they will be stored?

String str1 = new String("Tech");
String str2 = new String("Beamers");

What will be the output of the following code in Java?

public class a {
    public static void main(String args[]){
       final String str1="social";
       final String str2="media";
       String str3=str1+str2;
       String str4="socialmedia";
       System.out.println(str3==str4); // Output
    }
}

What is the result of the below lines of code?

String word = "abcde";
for (int i = 0; i<4; i+=2) {
   System.out.print(word[i]);
}

What is the result of the below lines of code?

    class Char_to_String {
        public static void main(String args[])
        {
            char chars[] = {'a', 'b', 'c'};
            String str = new String(chars);
            System.out.println(str);
        }
   }

What is the result of the below lines of code?

    class ascii_to_String {
        public static void main(String args[])
        {
            int ascii[] = { 65, 66, 67, 68};
            String str = new String(ascii, 1, 3);
            System.out.println(str);
        }
   }

What is the result of the below lines of code?

   class MyNum {
        int i;
	int j;
        void A() {
            i = 1;
            j = 2;
        }
   }
   class MyStr {
        public static void main(String args[])
        {
             MyNum testObj = new MyNum();
	     System.out.print(testObj.toString());
        }
   }

What is the result of the below lines of code?

public class TestStrings {
	public static void main(String params[]){
		String StrArr[]={"JAVA","JDK","JRE"};
		String Str="JAVA";
		System.out.println(StrArr[0]==Str);
	}
}

What is the result of the below lines of code?

String str1 = "How are you?";
String str2 = str1.substring(5, 7);
System.out.println(str2);

What is the result of the below lines of code?

String Str1 = " Java ";
String Str2 = " is ";
String Str3 = " awesome .";
String StrResult  = Str1.trim() + Str2 + Str3.trim();
System.out.println(StrResult);

Which of the following defines the value contained in testStr?
String testStr = “”;

Which of the following is true for an object having no reference variables referring to it?

Which of the following is the outcome of the below Java program?

public class JavaQuiz{
	private int i = j;
	private int j = 10;
	public static void main(String args[]){
		System.out.println((new JavaQuiz()).i);
	}
}