Ndtyjky

I ran into some code that has the following:

String foo = getvalue("foo");

if (StringUtils.isBlank(foo))

    doStuff();

else

    doOtherStuff();

This appears to be functionally equivalent to the following:

String foo = getvalue("foo");

if (foo.isEmpty())

    doStuff();

else

    doOtherStuff();

Is a difference between the two (org.apache.commons.lang3.StringUtils.isBlank and java.lang.String.isEmpty)?

StringUtils.isBlank() checks that each character of the string is a whitespace character (or that the string is empty or that it's null). This is totally different than just checking if the string is empty.

From the linked documentation:

Checks if a String is whitespace, empty ("") or null.

 StringUtils.isBlank(null)      = true

 StringUtils.isBlank("")        = true  

 StringUtils.isBlank(" ")       = true  

 StringUtils.isBlank("bob")     = false  

 StringUtils.isBlank("  bob  ") = false

The accepted answer from @arshajii is totally correct. However just being more explicit by saying below,

StringUtils.isBlank()

 StringUtils.isBlank(null)      = true

 StringUtils.isBlank("")        = true  

 StringUtils.isBlank(" ")       = true  

 StringUtils.isBlank("bob")     = false  

 StringUtils.isBlank("  bob  ") = false

StringUtils.isEmpty

 StringUtils.isEmpty(null)      = true

 StringUtils.isEmpty("")        = true  

 StringUtils.isEmpty(" ")       = false  

 StringUtils.isEmpty("bob")     = false  

 StringUtils.isEmpty("  bob  ") = false

StringUtils isEmpty = String isEmpty checks + checks for null.

StringUtils isBlank = StringUtils isEmpty checks + checks if the text contains only whitespace character(s).

Useful links for further investigation:

• StringUtils isBlank documentation


• StringUtils isEmpty documentation


• String isEmpty documentation

StringUtils.isBlank() will also check for null, whereas this:

String foo = getvalue("foo");

if (foo.isEmpty())

will throw a NullPointerException if foo is null.

StringUtils.isBlank also returns true for just whitespace:

isBlank(String str)

Checks if a String is whitespace, empty ("") or null.

StringUtils.isBlank(foo) will perform a null check for you. If you perform foo.isEmpty() and foo is null, you will raise a NullPointerException.

StringUtils.isBlank() returns true for blanks(just whitespaces)and for null String as well. Actually it trims the Char sequences and then performs check.

StringUtils.isEmpty() returns true when there is no charsequence in the String parameter or when String parameter is null. Difference is that isEmpty() returns false if String parameter contains just whiltespaces. It considers whitespaces as a state of being non empty.