When you want to convert a String to int or Integer you can use two simple methods from the Integer class.
To convert a String to primitive int use Integer.parseInt(String s)
String a = "1234"; int x = Integer.parseInt(a); |
To convert a String to an instance of Integer use Integer.valueOf(String s)
String a = "1234"; Integer x = Integer.valueOf(a); |
A common mistake Java novices do is using the == operator to compare Strings. This does almost certainly lead to unexpected and unwanted behaviour. There is a simple solution to this problem and a not so simple explanation why it is such a common mistake.
The simple solution is to use String.equals instead of the == operator.
So when you want to know if two String objects hold the same value instead of
String a = "Test"; String b = "Test"; if (a == b) { // Do something } |
just use this:
String a = "Test"; String b = "Test"; if (a.equals(b)) { // Do something } |
But look out for null Strings, == handles null Strings nicely but when you call
String a = null; String b = "Test"; if (a.equals(b)) { // Do something } |
it will result in a NullPointerException!
Sometimes you can’t wait for Firefox’s built in update mechanism to update you addons. Say you want to let your addon check for a new version on every startup of Firefox and then trigger the installtion of the new version. This can be done with a short Snippet:
This code surely could use some error handling and such, so feel free to throw your enhancements at me!