String Manipulation Interview questions?

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String concat,replace, substring, trim, lowercase, uppercase? Selenium, Automation core java interview questions?

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public class StringManipulation {

    public static void main(String[] args) {
        // Strings are immutable
        String str3 = "java";
        str3.concat("oops");
        System.out.println(str3); // java

        // The result should be assigned to a new reference variable (or same
        // variable) can be reused.
        String concat = str3.concat("value2");
        System.out.println(concat); // value1value2

        // -----------------------String methods-------------------------------------
        String str = "abcdefghijk";

        // char charAt(int paramInt)
        System.out.println(str.charAt(2)); // prints a char - c

        // String concat(String paramString)
        System.out.println(str.concat("lmn"));// abcdefghijklmn

        System.out.println("ABC".equalsIgnoreCase("abc"));// true
        System.out.println("ABCDEFGH".length());// 8

        // String replace(char paramChar1, char paramChar2)
        System.out.println("012301230123".replace('0', '4'));// 412341234123

        // String replace(CharSequence paramCharSequence1, CharSequence
        // paramCharSequence2)
        System.out.println("012301230123".replace("01", "45"));// 452345234523

        // All characters from index paramInt
        // String substring(int paramInt)
        System.out.println("abcdefghij".substring(3)); // defghij
        // 0123456789

        // All characters from index 3 to 6
        System.out.println("abcdefghij".substring(3, 7)); // defg
        // 0123456789

        System.out.println("ABCDEFGHIJ".toLowerCase()); // abcdefghij

        System.out.println("abcdefghij".toUpperCase()); // ABCDEFGHIJ

        System.out.println("abcdefghij".toString()); // abcdefghij

        // trim removes leading and trailings spaces
        System.out.println(" abcd  ".trim()); // abcd
    }
}

 

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What we know about the "STRING"?

 

MCQ on String for concepts and interview preparation QAE - SDET - AUTOMATION QA 2022

1. What is the output for below?

String str1 = "test";
String str2 = "one";

String str3 = str1.concat(str2);

Ans:

a) testone

b) test

c) one

d) Let me check in IDE :)

2. What is the output for below?

String str1 = "test";
String str2 = "test";

String str3 = new String("test");

System.out.println(str1.equals(str2));

System.out.println(str1.equals(str3));

Ans:

a) true,true

b) false, true

c) false, false

d) Let me check in IDE :)

3. What is the output for below?

String str1 = "test";

String str2 = "test";

String str3 = new String("test");

System.out.println(str1==str2));

System.out.println(str1==str3);

a) true, true

b) true, false

c) false, true

d) false, false

4. What is the output for below?

String str = "test";

System.out.println(str1.charAt(2)); 

a) s

b) e

c) error

d) es

5. What is the output for below?

System.out.println("012301230123".replace(55, "45"));

 System.out.println("012301230123".replace("01", "45"));

a) compile error, 452345234523

b) 452345234523, 452345234523

c) error, error

d) Let me check in IDE :)

6. What is the output for below?

System.out.println("tes".substring(3));

System.out.println("test".substring(3));

a) error, error

b) error, t

c)  , t

d) t, t

7. How many ways we can create String Object in Java?

a) String s = "abc"; String s1 = new String("abc");

b) Literal, Keyword

c)  Both A and B

d)  Not sure

8. Is String thread safe?

a) true

b) false

c) Not sure

9. What is the output for below?

String str8 = new StringBuilder("test").reverse().toString();

System.out.println(str8);

a) test

b) tset

c) Not sure

10. Which one is thread safe: StringBuffer or StringBuffer ?

a) Both

b) StringBuffer

c) StringBuilder

d) None of the options

Below are the answers for all the questions on STRING:

1. a)testone

2. a)true,true

3. b)true, false

4. a)S

5. a) compile error, 452345234523

6. c)  , t

7. c)  Both A and B

8. a) true

9. b) tset