StringBuilder is same as StringBuffer except that StringBuilder is not synchronized, hence it is not thread-safe.
i.e. StringBuilder class objects are non-thread-safe , mutable sequence of characters.
Note: StringBuilder not override equals method of object class, so StringBuilder objects should be converted into string objects if you want to compare StringBuilder class objects.
Constructors of StringBuffer class:
1. public StringBuilder (): creates a string builder with no characters and with default capacity 16 i.e. it can contain 16 characters.
2. public StringBuilder (int capacity): creates a string builder with no characters and with specified capacity.
Note: capacity should not be less than zero , otherwise it will throw NegativeArraySizeException.
3. public StringBuilder (String str):creates a string builder with specified string as initial content.
Initial capacity = Default capacity + length of the string.
- String should not be null otherwise it will throw NullPointerException.
- If string length is equal to zero than string builder with no content and default capacity is return.
4. public StringBuilder (CharSequence charSquence):creates a string builder with specified character sequence as its initial content.
- charSquence should not be null otherwise it will throw NullPointerException.
- if charSquence length is equal to zero than string builder with no content and default capacity is return.
Commonly used methods of StringBuilder class:
|1.||append(String str)||Append the specified string at the end of this string.|
|2.||insert(int offset, String str)||Insert specified string at the offset indicated position.|
|3.||replace(int startIndex, int endIndex, String str)||Replace the substring of the string builder from startIndex to endIndex-1 with specified string.|
|4.||delete(int startIndex, int endIndex)||delete the substring of the string builder from startIndex to endIndex-1.|
|5.||reverse()||replace the string builder’s character sequence by reverse character sequence.|
|6.||capacity()||returns the current capacity of string builder. Capacity refers to the amount of available storage.|
|7.||ensureCapacity(int minCapacity)||ensures that the capacity is at least equal to the specified minimum.|