Common Java String Interview Questions

Here are some commonly asked interview questions related to Java Strings:

1. What is a String in Java and how is it different from a primitive data type like int or char?
2. How do you create a String in Java?
3. What is the difference between a string literal and a string object in Java?
4. What is the significance of the String class in Java?
5. What are some of the methods available in the String class in Java?
6. Can you concatenate two strings in Java? How would you do it?
7. What is string immutability in Java?
8. How does the String Pool work in Java?
9. How would you compare two strings in Java?
10. Can you explain the use of the equals() and equalsIgnoreCase() methods in Java?
11. How would you find the length of a string in Java?
12. What is the difference between the length() method and the length property in Java?
13. How would you reverse a string in Java?
14. Can you explain the difference between the substring() and the substring() method in Java?
15. What are some of the commonly used string manipulation techniques in Java?
16. How would you find the first occurrence of a substring in a string in Java?
17. Can you explain the use of the indexOf() and lastIndexOf() methods in Java?
18. What is the difference between the trim() and the replace() methods in Java?
19. Can you explain the use of the split() method in Java?
20. How would you convert a string to uppercase or lowercase in Java?
21. Can you explain the use of the toCharArray() method in Java?
22. Can you explain the use of the valueOf() method in Java?
23. How would you compare two strings without using the equals() method in Java?
24. Can you explain the difference between a StringBuilder and a StringBuffer in Java?
25. What is the use of the StringTokenizer class in Java?
26. Can you explain the difference between the + and the concat() method for string concatenation in Java?
27. How would you check if a string contains a certain character or substring in Java?
28. Can you explain the use of the startsWith() and endsWith() methods in Java?
29. How would you extract a portion of a string in Java?
30. Can you explain the use of the compareTo() method in Java?
31. How would you sort an array of strings in Java?
32. Can you explain the difference between the == and the equals() method for string comparison in Java?
33. How would you change the case of characters in a string in Java?
34. Can you explain the use of the StringWriter and StringReader classes in Java?
35. How would you find the number of occurrences of a substring in a string in Java?
36. Can you explain the difference between the String and StringBuffer classes in Java?
37. How would you replace a character in a string in Java?
38. Can you explain the use of the StringJoiner class in Java?
39. How would you check if a string is a palindrome in Java?
40. Can you explain the difference between the substring() and the subSequence() methods in Java?
41. How would you find the first non-repeated character in a string in Java?
42. Can you explain the use of the format() method in Java?
43. How would you remove duplicates from a string in Java?
44. Can you explain the use of the CharSequence interface in Java?
45. How would you find the longest common prefix of two strings in Java?