Best Practice, Writing efficient Code for Blackberry Apps

To allow a BlackBerry® Java® Application to use resources efficiently, consider the following guidelines:

• Using local variables
  
• Using shorthand for evaluating Boolean conditions
  
• Making classes final
  
• Using int instead of long
  
• Avoiding garbage collection
  
• Using static variables for Strings
  
• Avoiding the String(String) constructor
  
• Writing efficient loops
  
• Optimizing subexpressions
  
• Optimizing division operations
  
• Avoiding java.util.Enumeration
  
• Performing casts using instanceof
  
• Evaluating conditions using instanceof
  
• Avoiding StringBuffer.append (StringBuffer)
  
• Avoiding returning null
  
• Avoiding passing null into methods
  
• Using caution when passing null into a constructor
  
• Using longs for unique identifiers
  
• Exiting applications correctly
  
• Printing the stack trace

source: http://docs.blackberry.com/en/developers/deliverables/5580/BP_Writing_efficient_code_446999_11.jsp