The
indexOf() method of
java.util.AbstractList class is used to return the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the lowest index i such that (o==null ? get(i)==null : o.equals(get(i))), or -1 if there is no such index.
Syntax:
public int indexOf(Object o)
Parameters: This method takes
Object o as parameter which is the element to search for.
Return Value: This method returns the
index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.
Below are the examples to illustrate the
indexOf() method.
Example 1:
Output:
ArrayListlist : [10, 20, 30, 40, 50]
index : 2
Example 2:
Output:
ArrayListlist : [10, 20, 30, 40, 50]
Index of 25 : -1
Example 3: For Null value
