Java StringBuilder.setLength() – Examples
In this tutorial, we will learn about the Java StringBuilder.setLength() function, and learn how to use this function to set a specific length for this StringBuilder sequence, with the help of examples.
setLength(int newLength)
StringBuilder.setLength() sets the length of this StringBuilder sequence.
Syntax
The syntax of setLength() function is
setLength(int newLength)
where
| Parameter | Description |
|---|---|
| newLength | New length for this StringBuilder sequence. |
Returns
The function returns void. Means, the function returns nothing.
Example 1 – setLength(newLength) – newLength > length
In this example, we will take a StringBuilder of length 6, and set its length to a new value of 10. Since, length of StringBuilder sequence is less than the new length, setLength() appends null characters to make it to the new length.
Java Program
public class Example {
public static void main(String[] args) {
StringBuilder stringBuilder = new StringBuilder("abcdef");
System.out.println("Value before setting : \"" + stringBuilder.toString()+"\"");
System.out.println("Length before setting : " + stringBuilder.length());
int newLength = 10;
stringBuilder.setLength(newLength);
System.out.println("Value after setting : \"" + stringBuilder.toString()+"\"");
System.out.println("Length after setting : " + stringBuilder.length());
}
} Output
Value before setting : "abcdef" Length before setting : 6 Value after setting : "abcdef " Length after setting : 10
Example 2 – setLength(newLength) – newLength < length
In this example, we will set a new length for StringBuilder such that the new length is less than the actual length of StringBuilder. In this case, setLength() trims out the excess characters and sets the length of StringBuilder to specified length.
Java Program
public class Example {
public static void main(String[] args) {
StringBuilder stringBuilder = new StringBuilder("abcdef");
System.out.println("Value before setting : \"" + stringBuilder.toString()+"\"");
System.out.println("Length before setting : " + stringBuilder.length());
int newLength = 4;
stringBuilder.setLength(newLength);
System.out.println("Value after setting : \"" + stringBuilder.toString()+"\"");
System.out.println("Length after setting : " + stringBuilder.length());
}
} Output
Value before setting : "abcdef" Length before setting : 6 Value after setting : "abcd" Length after setting : 4
Example 3 – setLength(newLength) – newLength < 0
A negative value for newLength makes setLength() throw ava.lang.StringIndexOutOfBoundsException.
Java Program
public class Example {
public static void main(String[] args) {
StringBuilder stringBuilder = new StringBuilder("abcdef");
System.out.println("Value before setting : \"" + stringBuilder.toString()+"\"");
System.out.println("Length before setting : " + stringBuilder.length());
int newLength = -5;
stringBuilder.setLength(newLength);
System.out.println("Value after setting : \"" + stringBuilder.toString()+"\"");
System.out.println("Length after setting : " + stringBuilder.length());
}
} Output
Value before setting : "abcdef" Length before setting : 6 Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -5 at java.base/java.lang.AbstractStringBuilder.setLength(Unknown Source) at java.base/java.lang.StringBuilder.setLength(Unknown Source) at Example.main(Example.java:8)
Conclusion
In this Java Tutorial, we have learnt the syntax of Java StringBuilder.setLength() function, and also learnt how to use this function with the help of examples.