Don't use a context other than that of the application when creating utility classes.
If you don't do this, this will eventually result in a memory leak.
Eg. you use the activity as the context parameter, and use this context in the utility for retrieving the default shared preferences.
When you go to another activity, the first one should be stopped & destroyed.
Instead of being GC'd it will still live in the heap because the default shared preferences uses this object.