I am new to java. Am unable to check for null. Could you enlighten me on this? I have string array which has no elements.
I tried this code
String[] k = new String[3];
if(k==null){
System.out.println(k.length);
}
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A better duplicate - How can I check whether an array is null / empty?Bernhard Barker– Bernhard Barker2017-09-12 18:20:23 +00:00Commented Sep 12, 2017 at 18:20
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5 Answers
Very precisely
if(k!=null && k.length>0){
System.out.println(k.length);
}else
System.out.println("Array is not initialized or empty");
k!=null would check array is not null. And StringArray#length>0 would return it is not empty[you can also trim before check length which discard white spaces].
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answered May 30, 2013 at 6:29
Subhrajyoti Majumder
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Comments
There's a key difference between a null array and an empty array. This is a test for null.
int arr[] = null;
if (arr == null) {
System.out.println("array is null");
}
"Empty" here has no official meaning. I'm choosing to define empty as having 0 elements:
arr = new int[0];
if (arr.length == 0) {
System.out.println("array is empty");
}
An alternative definition of "empty" is if all the elements are null:
Object arr[] = new Object[10];
boolean empty = true;
for (int i=0; i<arr.length; i++) {
if (arr[i] != null) {
empty = false;
break;
}
}
or
Object arr[] = new Object[10];
boolean empty = true;
for (Object ob : arr) {
if (ob != null) {
empty = false;
break;
}
}
Comments
if (myArray == null)
System.Console.WriteLine("array is not initialized");
else if (myArray.Length < 1)
System.Console.WriteLine("array is empty");
Comments
String k[] = new String[3];
if(k.length == 0 ){
System.out.println("Null");
}
it will display null if there is no item in array.
Comments
I think you can use this:
if(str != null && !str.isEmpty())
UPDATE
Better solution is this one:
TextUtils.isEmpty(str)
1 Comment
Anahit Serobyan
There is no 'isEmpty()' method for string arrays in java.