Is it safe to save Application Context to static variable

Question

I made Cache class that use SharedPreferences.
It contains below methods.

• static save(Context context, String key, Mixed value) (Mixed: String, long, int, double, ...)
• static load[Type](Context context, String key) (loadString, loadInt, loadDouble, ...)
• static exists(Context context, String key)

These methods contain a Context parameter.
Because Context is necessary to use SharedPreferences.
I think it is very uncomfortable.

So I modify the class like below.

• private static Context context
• static init(Context context): save context to static context
• static save(String key, Mixed value)
• static load[Type](String key)
• static exists(String key)

or

• private static SharedPreferences sp
• static init(Context context)
  • save context.getSharedPreferences(...) to static sp
• static save(String key, Mixed value)
• static load[Type](String key)
• static exists(String key)

init method will call at SplashActivity like Cache.init(getApplicationContext()). (SplashActivity is Launcher Activity)

This is a safe way? or is any better way?