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 */ }
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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 */ }
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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
Baeldung
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 - String#isEmpty was introduced with ... String#isEmpty is just a shortcut to String#length. Both String#isEmpty and String#length can be used to check for empty strings....
Shorter (efficient) way to check if a string is null or empty?
[The Java String class has an isEmpty method]( https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#isEmpty() More on reddit.com
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March 4, 2020Best Way to Check if a String is Null or Empty in Java - TestMu AI Community
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 follow… More on community.testmuai.com
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March 19, 2025java - Check for empty string null? - Stack Overflow
But every time my above method returns back me as false for above userId? It should true since userId is null. Is there any other api in Guava or Apache Commons which can do this? ... @david There may be libraries that check for null and empty, but I don't think they check for the string "null". More on stackoverflow.com
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
Here’s the condition I wrote ... string.equals(""). I also heard that using equals("") might not be the right approach. So, how can I java check if string is empty or null in a safe and reliab...... More on community.testmu.ai
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Stack Abuse
stackabuse.com › java-check-if-string-is-null-empty-or-blank
Java: Check if String is Null, Empty or Blank
February 28, 2023 - String string = "Hello there"; if (string == null || string.equals("") || string.trim().equals("")) System.out.println("String is null, empty or blank"); else System.out.println("String is neither null, empty nor blank"); In much the same fashion as the before, if the trimmed string is "", ...
Medium
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 - In Java, calling a method on a null reference will result in a NullPointerException, one of the most common runtime errors. To prevent this, it is crucial to check for null before performing operations on a variable. An empty String ("") has zero characters but still exists in memory, specifically in the heap where Java stores objects.
Vultr Docs
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.
Codemia
codemia.io › knowledge-hub › path › checking_if_a_string_is_empty_or_null_in_java
Checking if a string is empty or null in Java
Enhance your system design skills with over 120 practice problems, detailed solutions, and hands-on exercises
CodeGym
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 - Java provides a built-in method to check for all those whitespaces in a String. Let’s look at an example on how to use that. public class Example2 { public static void main(String[] args) { // check if it is a "blank" string String myName = new String(" \t \n \t \t "); System.out.println("The String = " + myName); System.out.println("Is the String null? " + (myName == null)); System.out.println("Is the String empty?
BeginnersBook
beginnersbook.com › 2022 › 10 › check-if-string-is-null-empty-or-blank-in-java
Check if String is Null, Empty or Blank in Java
January 7, 2023 - String myString = ""; //empty string ... method doesn’t return true for blank String. However there is a way to check blank string combining the isEmpty() method with trim() method....
Reddit
reddit.com › r/learnjava › shorter (efficient) way to check if a string is null or empty?
Shorter (efficient) way to check if a string is null or empty? : r/learnjava
March 4, 2020 - [The Java String class has an isEmpty method](https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#isEmpty() ... That's correct, but his left hand condition will check for that, if its true the right hand condition will not be evaluated ... This is TERRIBLE advice. The point of evaluating a variable is so that the program doesn't crash. Yet, your advice is to let the application crash. That is in no way better than checking that the variable is null or empty.
TestMu AI Community
community.testmuai.com › ask a question
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.
W3Schools
w3schools.com › java › ref_string_isempty.asp
Java String isEmpty() Method
String myStr1 = "Hello"; String myStr2 = ""; System.out.println(myStr1.isEmpty()); System.out.println(myStr2.isEmpty()); ... The isEmpty() method checks whether a string is empty or not.
Programiz
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. ...
Quora
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...
Quora
quora.com › Is-there-a-better-way-to-do-an-empty-check-in-Java
Is there a better way to do an empty check in Java? - Quora
Answer (1 of 2): You’ve got the Apache StringUtils stuff which has methods like isNotBlank and methods to use a default String. Great for null/empty/space checks on String More generally, there are many ways of conveying empty in Java. None of them are good.
Top answer 1 of 3
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The value null is not equal to the String "null". null means that a given object has not been assigned a value, where the String "null" is a valid object. It contains the characters n u l l, which is a valid value for a String. You need to also check if the value is the literal string "null" in order to do what you want.
Correct Check
return value == null || value.isEmpty() || value.equals("null") ;
If you want to still maintain "null" as a valid username, then change whatever is sending the json to the following format, which should be interpreted as a literal null rather than a String with content "null"
"userId":null
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"null" is not the same as null.
"null" is a string 4 characters in length of the word "null".
null (no quotes) is just that--nothing.
Oracle
docs.oracle.com › javaee › 7 › tutorial › bean-validation002.htm
21.2 Validating Null and Empty Strings - Java Platform, Enterprise Edition: The Java EE Tutorial (Release 7)
if (testString==null) { doSomething(); } else { doAnotherThing(); } By default, the doAnotherThing method is called even when the user enters no data, because the testString element has been initialized with the value of an empty string. In order for the Bean Validation model to work as intended, ...
Blogger
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
If you are a complete beginner then I suggest you first go through a comprehensive course like The Complete Java Masterclass on Udemy to learn more about core Java basics as well as such gems from Java API. Here are my three solutions to this common problem. Each solution has its pros and cons and a special use case like the first solution can only be used from JDK 7 onward, the second is the fastest way to check if String is empty and the third solution should be used if your String contains whitespaces. This is the most readable way to check for both whether String is null or not and whether String is empty or not.
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 5, 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"); }…
Coderanch
coderanch.com › t › 203109 › java › Efficient-Check-Empty-String
Efficient Way to Check Empty String (Performance forum at Coderanch)
We use (string != null || string.trim().length() == 0) to check if string is empty. Calling a method which actually iterate through string and checks for non-whitespace character .
Coderanch
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)
May 1, 2018 - Hi, Why not write a program to do the job, and then simply call this program with the variable arguments? Here is an example. The Consumer<String> process is your actual program. The rest is just testing environment: ... Yes, Means in programming we need to check null values every time to save program from the null exception while execution.