Check whether a String is not Null and not Empty

stackoverflow.com › questions › 3598770 › check-whether-a-string-is-not-null-and-not-empty

What about isEmpty() ?

if(str != null && !str.isEmpty())

Be sure to use the parts of && in this order, because java will not proceed to evaluate the second part if the first part of && fails, thus ensuring you will not get a null pointer exception from str.isEmpty() if str is null.

Beware, it's only available since Java SE 1.6. You have to check str.length() == 0 on previous versions.

To ignore whitespace as well:

if(str != null && !str.trim().isEmpty())

(since Java 11 str.trim().isEmpty() can be reduced to str.isBlank() which will also test for other Unicode white spaces)

Wrapped in a handy function:

public static boolean empty( final String s ) {
  // Null-safe, short-circuit evaluation.
  return s == null || s.trim().isEmpty();
}

Becomes:

if( !empty( str ) )

Answer from Colin Hebert on Stack Overflow

geeksforgeeks.org › java › program-to-check-if-the-string-is-null-in-java

Program to check if the String is Null in Java - GeeksforGeeks

July 12, 2025 - The below example demonstrates how to check if a given string is null using the == relational operator. ... // Java Program to check if // a String is Null class StringNull { // Method to check if the String is Null public static boolean ...

codegym.cc › java blog › strings in java › java: check if string is null, empty or blank

Java: Check if String is Null, Empty or Blank

October 11, 2023 - Also, you can use the example below to check if a string is null or empty. public class Example1 { public static void main(String[] args) { // check if it is an "empty" string String myName = new String(); System.out.println("The String = " + myName); // not sure if the string is either null or empty System.out.println("Is the String null?

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javarevisited.blogspot.com › 2016 › 01 › how-to-check-if-string-is-not-null-and-empty-in-java-example.html

How to check if String is not null and empty in Java? Example

Since we are first doing a null check and then an empty check using the && operator, which is a short circuit AND operator. This operator will not check for emptiness if String is null hence no NPE. This is also a good trick to avoid NPE in Java.

stackoverflow.com › questions › 3598770 › check-whether-a-string-is-not-null-and-not-empty

java - Check whether a String is not Null and not Empty - Stack Overflow

What about isEmpty() ?

if(str != null && !str.isEmpty())

Be sure to use the parts of && in this order, because java will not proceed to evaluate the second part if the first part of && fails, thus ensuring you will not get a null pointer exception from str.isEmpty() if str is null.

Beware, it's only available since Java SE 1.6. You have to check str.length() == 0 on previous versions.

To ignore whitespace as well:

if(str != null && !str.trim().isEmpty())

(since Java 11 str.trim().isEmpty() can be reduced to str.isBlank() which will also test for other Unicode white spaces)

Wrapped in a handy function:

public static boolean empty( final String s ) {
  // Null-safe, short-circuit evaluation.
  return s == null || s.trim().isEmpty();
}

Becomes:

if( !empty( str ) )

Use org.apache.commons.lang.StringUtils

I like to use Apache commons-lang for these kinds of things, and especially the StringUtils utility class:

import org.apache.commons.lang.StringUtils;

if (StringUtils.isNotBlank(str)) {
    ...
} 

if (StringUtils.isBlank(str)) {
    ...
}

medium.com › @ecetasci.iu › checking-for-null-or-empty-strings-in-java-19518fa1e553

Checking for Null or Empty Strings in Java | by Ece Tasci | Medium

February 25, 2025 - When working with Strings in Java, it is common to encounter situations where a String might be either null or empty. This can lead to unexpected errors, particularly when working with user input, API responses, or database records. To avoid these issues, performing proper checks before using a String in operations like concatenation, comparison, or storage is essential. One of the most common ways to ensure a String is valid before using it is by checking if(name != null && !name.isEmpty()).

stackoverflow.com › questions › 5499809 › how-to-check-a-string-is-not-null

java - How to check a string is not null? - Stack Overflow

Checking for null is done via if (string != null)

If you want to check if its null or empty - you'd need if (string != null && !string.isEmpty())

I prefer to use commons-lang StringUtils.isNotEmpty(..)

You can do it with the following code:

 if (string != null) {

 }

stackoverflow.com › questions › 14721397 › checking-if-a-string-is-empty-or-null-in-java

Checking if a string is empty or null in Java - Stack Overflow

Correct way to check for null or empty or string containing only spaces is like this:

if(str != null && !str.trim().isEmpty()) { /* do your stuffs here */ }

You can leverage Apache Commons StringUtils.isEmpty(str), which checks for empty strings and handles null gracefully.

Example:

System.out.println(StringUtils.isEmpty("")); // true
System.out.println(StringUtils.isEmpty(null)); // true

Google Guava also provides a similar, probably easier-to-read method: Strings.isNullOrEmpty(str).

Example:

System.out.println(Strings.isNullOrEmpty("")); // true
System.out.println(Strings.isNullOrEmpty(null)); // true

stackabuse.com › java-check-if-string-is-null-empty-or-blank

Java: Check if String is Null, Empty or Blank

February 28, 2023 - The equals() method compares the two given strings based on their content and returns true if they're equal or false if they are not: String string = "Hello there"; if (string == null || string.equals("") || string.trim().equals("")) System.out.println("String is null, empty or blank"); else ...

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docs.vultr.com › java › examples › check-if-a-string-is-empty-or-null

Java Program to Check if a String is Empty or Null | Vultr Docs

December 17, 2024 - public static boolean isNullOrEmpty(String str) { return str == null || str.isBlank(); } Explain Code · With Java 11, String.isBlank() does what StringUtils.isBlank() from Apache Commons does but without the need for an external library. Checking if a string is empty or null in Java can be approached in multiple ways, each serving different needs depending on your project requirements.

reddit.com › r/java › cleanest way to check for null on a string?

Cleanest way to check for null on a String? : r/java

May 8, 2024 - The advantage with the switch is you can add more conditions easily and you can switch to @Nullable String later if you choose (I avoid Optional unless its API like Service). I admit though I would probably pick what u/Equivalent_Plan_3076 proposing if for sure you want to use Optional. I'm not a fan of u/papercrane java.util.Objects.toString(Object o, String nullDefault) because the second argument is @PolyNull and the JDK javadoc description barely makes it clear that it is.

quora.com › How-do-perform-a-Null-check-for-string-in-Java

How do perform a Null check for string in Java? - Quora

Answer (1 of 7): 4 Ways to check if String is null or empty in Java:- Here are my four solutions for this common problem. Each solution has their pros and cons and a special use case e.g. first solution can only be used from JDK7 on wards, second solution is the fastest way to check string is em...

programiz.com › java-programming › examples › string-empty-null

Java Program to Check if a String is Empty or Null

This is because white spaces are treated as characters in Java and the string with white spaces is a regular string. Now, if we want the program to consider strings with white spaces as empty strings, we can use the trim() method. The method removes all the white spaces present in a string. ...

stackoverflow.com › questions › 2601978 › how-to-check-if-my-string-is-equal-to-null

java - How to check if my string is equal to null? - Stack Overflow

Copyif (myString != null && !myString.isEmpty()) {
  // doSomething
}

As further comment, you should be aware of this term in the equals contract:

From Object.equals(Object):

For any non-null reference value x, x.equals(null) should return false.

The way to compare with null is to use x == null and x != null.

Moreover, x.field and x.method() throws NullPointerException if x == null.

If myString is null, then calling myString.equals(null) or myString.equals("") will fail with a NullPointerException. You cannot call any instance methods on a null variable.

Check for null first like this:

Copyif (myString != null && !myString.equals("")) {
    //do something
}

This makes use of short-circuit evaluation to not attempt the .equals if myString fails the null check.

TestMu AI Community

community.testmu.ai › ask a question

What is the correct way to check if a String is empty or null in Java, and how can I avoid potential errors? - TestMu AI Community

March 4, 2025 - I’m parsing HTML data, and sometimes the string might be either null or an empty string. Here’s the condition I wrote to handle it: if(string.equals(null) || string.equals("")){ Log.d("iftrue", "seem to be true"); }…

beginnersbook.com › 2022 › 10 › check-if-string-is-null-empty-or-blank-in-java

Check if String is Null, Empty or Blank in Java

Simply compare the string with null to check for null string. Use isEmpty() method of string class to check for empty string. The isEmpty() method returns true if the string does not contain any value. Use trim() and isEmpty() method together to check for blank string.

tutorialspoint.com › checking-for-null-or-empty-in-java

Checking for Null or Empty in Java.

The following are the ways to check if a string is null or empty in Java: ... The isEmpty() method of the String class checks if a string is empty. It returns TRUE if the string has no characters, and FALSE otherwise. Following is an example of checking if a string is null or empty using the ...

baeldung.com › home › java › java string › checking for empty or blank strings in java

Checking for Empty or Blank Strings in Java | Baeldung

January 8, 2024 - The most convenient way is to use Apache Commons Lang, which provides helpers such as StringUtils.isBlank. If we want to stick to plain Java, we can use a combination of String#trim with either String#isEmpty or String#length.

coderanch.com › t › 693624 › java › check-null-empty-strings-time

Do we have any way to check null value and empty strings all the time ? (Features new in Java 8 forum at Coderanch)

If I go into the first class, what are you going to do about the middle name I haven't got? Mark it null? But in the second version, you can have an array with all middle names in; in my case you can use a zero‑length array. Abracadabra! No nulls More details in books like Effective Java by Joshua Bloch.

tutorialspoint.com › check-if-a-string-is-not-empty-and-not-null-in-java

Check if a String is not empty ("") and not null in Java

JavaObject Oriented ProgrammingProgramming · Let’s say we have the following string − · String myStr1 = "Jack Sparrow"; Let us check the string now whether it is not null or not empty. if(myStr != null || myStr.length() != 0) { System.out.println("String is not null or not empty"); Live Demo ·

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Best Way to Check if a String is Null or Empty in Java - TestMu AI Community

March 19, 2025 - What is the best way to check if a String is null or empty in Java? I’m currently parsing HTML data, and sometimes the String can be null or empty when the expected word doesn’t match. To handle this, I wrote the following check: if(string.equals(null) || string.equals("")){ Log.d("iftrue", "seem to be true"); }else{ Log.d("iffalse", "seem to be false"); } However, when I remove string.equals(""), the condition doesn’t work correctly.