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Check if a String is whitespace, empty ("") or null in Java
Let’s say the following is our string.
String myStr = "";
Now, we will check whether the above string is whitespace, empty ("") or null.
if(myStr != null && !myStr.isEmpty() && !myStr.trim().isEmpty()) {
System.out.println("String is not null or not empty or not whitespace");
} else {
System.out.println("String is null or empty or whitespace");
}The following is an example that checks for an empty string.
Example
public class Demo {
public static void main(String[] args) {
String myStr = "";
if(myStr != null && !myStr.isEmpty() && !myStr.trim().isEmpty()) {
System.out.println("String is not null or not empty or not whitespace");
} else {
System.out.println("String is null or empty or whitespace");
}
}
}Output
String is null or empty or whitespace
Let us see another example that checks for whitespace input.
Example
public class Demo {
public static void main(String[] args) {
String myStr = " ";
if(myStr != null && !myStr.isEmpty() && !myStr.trim().isEmpty()) {
System.out.println("String is not null or not empty or not whitespace");
} else {
System.out.println("String is null or empty or whitespace");
}
}
}Output
String is null or empty or whitespace
Updated on: 27-Jun-2020
1K+ Views
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