methods of string builder

• StringBuilder(): Constructs a string builder with no characters in it and an initial capacity of 16 characters.
• StringBuilder(int capacity): Constructs a string builder with no characters in it and an initial capacity specified by the capacity argument.
• StringBuilder(CharSequence seq): Constructs a string builder that contains the same characters as the specified CharSequence.
• StringBuilder(String str): Constructs a string builder initialized to the contents of the specified string. 

lder   import java.util.*; import java.util.concurrent.LinkedBlockingQueue;   public class GFG1 {     public static void main(String[] argv) throws Exception     {         // Create a StringBuilder object         // using StringBuilder() constructor         StringBuilder str = new StringBuilder();           str.append("GFG");           // print string         System.out.println("String = " + str.toString());           // create a StringBuilder object         // using StringBuilder(CharSequence) constructor         StringBuilder str1             = new StringBuilder("AAAABBBCCCC");           // print string         System.out.println("String1 = " + str1.toString());           // create a StringBuilder object         // using StringBuilder(capacity) constructor         StringBuilder str2 = new StringBuilder(10);           // print string         System.out.println("String2 capacity = "                            + str2.capacity());           // create a StringBuilder object         // using StringBuilder(String) constructor         StringBuilder str3             = new StringBuilder(str1.toString());           // print string         System.out.println("String3 = " + str3.toString());     } }

Output

String = GFG
String1 = AAAABBBCCCC
String2 capacity = 10
String3 = AAAABBBCCCC

Methods in Java StringBuilder

StringBuilder append(X x): This method appends the string representation of the X type argument to the sequence.

1. StringBuilder appendCodePoint(int codePoint): This method appends the string representation of the codePoint argument to this sequence.
2. int capacity(): This method returns the current capacity.
3. char charAt(int index): This method returns the char value in this sequence at the specified index.
4. IntStream chars(): This method returns a stream of int zero-extending the char values from this sequence.
5. int codePointAt(int index): This method returns the character (Unicode code point) at the specified index.
6. int codePointBefore(int index): This method returns the character (Unicode code point) before the specified index.
7. int codePointCount(int beginIndex, int endIndex): This method returns the number of Unicode code points in the specified text range of this sequence.
8. IntStream codePoints(): This method returns a stream of code point values from this sequence.
9. StringBuilder delete(int start, int end): This method removes the characters in a substring of this sequence.
10. StringBuilder deleteCharAt(int index): This method removes the char at the specified position in this sequence.
11. void ensureCapacity(int minimumCapacity): This method ensures that the capacity is at least equal to the specified minimum.
12. void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin): This method characters are copied from this sequence into the destination character array dst.
13. int indexOf(): This method returns the index within this string of the first occurrence of the specified substring.
14. StringBuilder insert(int offset, boolean b): This method inserts the string representation of the boolean alternate argument into this sequence.
15. StringBuilder insert(): This method inserts the string representation of the char argument into this sequence.
16. int lastIndexOf(): This method returns the index within this string of the last occurrence of the specified substring.
17. int length(): This method returns the length (character count).
18. int offsetByCodePoints(int index, int codePointOffset): This method returns the index within this sequence that is offset from the given index by codePointOffset code points.
19. StringBuilder replace(int start, int end, String str): This method replaces the characters in a substring of this sequence with characters in the specified String.
20. StringBuilder reverse(): This method causes this character sequence to be replaced by the reverse of the sequence.
21. void setCharAt(int index, char ch): In this method, the character at the specified index is set to ch.
22. void setLength(int newLength): This method sets the length of the character sequence.
23. CharSequence subSequence(int start, int end): This method returns a new character sequence that is a subsequence of this sequence.
24. String substring(): This method returns a new String that contains a subsequence of characters currently contained in this character sequence.
25. String toString(): This method returns a string representing the data in this sequence.
26. void trimToSize(): This method attempts to reduce storage used for the character sequence.