Converting a String array into an int Array in java

To get rid of additional whitespace, you could change the code like this:

intarray[i]=Integer.parseInt(str.trim()); // No more Exception in this line

To help debug, and make your code better, do this:

private void processLine(String[] strings) {
    Integer[] intarray=new Integer[strings.length];
    int i=0;
    for(String str:strings){
        try {
            intarray[i]=Integer.parseInt(str);
            i++;
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException("Not a number: " + str + " at index " + i, e);
        }
    }
}

Also, from a code neatness point, you could reduce the lines by doing this:

for (String str : strings)
    intarray[i++] = Integer.parseInt(str);

Another short way:

int[] myIntArray = Arrays.stream(myStringArray).mapToInt(Integer::parseInt).toArray();

Suppose, for example, that we have a arrays of strings:

String[] strings = {"1", "2", "3"};

With Lambda Expressions^{[1] [2]} (since Java 8), you can do the next ▼:

int[] array = Arrays.asList(strings).stream().mapToInt(Integer::parseInt).toArray();

▼ This is another way:

int[] array = Arrays.stream(strings).mapToInt(Integer::parseInt).toArray();

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Notes
  1. Lambda Expressions in The Java Tutorials.
  2. Java SE 8: Lambda Quick Start}