XSPELSODE

XSPELSODE

1. Garbage Collection

   • under the control of the JVM; decides when to run it
   • System.gc() ask the JVM to run the GC but no guarantees
   • Make Objects Eligible for GC
     • Nulling a Reference
     • Reassigning a Reference Variable
     • Isolating a Reference
   • only thing guaranteed GC will run before it throws an OutOfMemoryException
   • new Objcect.finalize() called only once to clean up resources before GC
     • might run, but you can't count on it; don't override finalize() at all
     • we can save an object from deletion inside it by making a reference to that object
       • If the object becomes eligible for GC later it will not run again

2. Loops and Iterators

   • while, do while, for
     • for(Declaration and initialization of same type, boolean expression, iteration expression)
       • declaration has loop scope not method
       • evaluating iteration expression then the conditional expression then enter block
       • all three sections are independent of each other: don't need to operate on the same variables
         • for (int a = 1; b != 1; System.out.println("iterate"))
         • for( ; ; ) endless loop
   • The Enhanced for (Arrays & Collections) for(item declaration: array)
   • Early Loop Termination: break, return, System.exit()
   • continue must be inside a loop otherwise compile time error
   • break must be inside a loop or swith statement otherwise compile time error
   • Labeled Statements
     • Labeled continue and break statements must be inside the loop that has the same label name, otherwise compile-time error
     • break outer; (by default break inner)