Exception Handling (三)

10 Best Practices With Exceptions

• 1 Relevancy
•      keep the exceptions you throw relevant to the interface.
• 2 Encapsulation
•     throws only exceptions that are relevant to the interface
• 3 Reason
•     The exceptions must always say what caused them=>To create a generic exception and describe what caused it
• 4 Exception names
•     My advice is to avoid using thejava.lang.Exception as it is too generic and gives too little information about what went wrong.
• 5 Balance what you catch

• } catch (ClassCastException e1) {
     ...
  } catch (FileNotFoundException e) {
     ... 
  } catch (IOException e) {
     ...
  }

• 6 Scoping
•     How long should a try block be?
• 7 Use Finally

• } finally {
      try {
        output.close();
      } catch (Throwable e) {
        e.printStackTrace();
      }
  }

• 8 Throw only Exceptions
• 9 Throw early catch late
•     you should throw an exception as soon as you can and catch it late, wait until you have all the information to handle it properly.
• 10 Add validation

• if ( null == variable || variable.isEmpty()){
     throw new blahException("the variable cannot be null at this point");
  }