...
| Code Block |
|---|
|
public class TestWrapper1 {
public static void main(String[] args) {
// Create an array list of integers, where each element
// is greater than 127
ArrayList<Integer> list1 = new ArrayList<Integer>();
for(int i=0;i<10;i++)
list1.add(i+1000);
// Create another array list of integers, where each element
// is the same as the first one
ArrayList<Integer> list2 = new ArrayList<Integer>();
for(int i=0;i<10;i++)
list2.add(i+1000);
int counter = 0;
for(int i=0;i<10;i++)
if(list1.get(i).equals(list2.get(i))) counter++;
System.out.println(counter);
}
}
|
Exceptions
EX1: Boolean variables can be compared using relational operators, however, if instantiated as an object this is counterproductive.
| Code Block |
|---|
|
Boolean b1 = new Boolean("true");
Boolean b2 = new Boolean("true");
if(b1 == b2) { // never equal
// ...
}
|
Use this instead:
| Code Block |
|---|
|
Boolean b1 = true;
Boolean b2 = true;
if(b1 == b2) { // always equal
// ...
}
|
Risk Assessment
Using the equal and not equal operators to compare boxed primitives can lead to erroneous comparisons.
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