17 

    18 * Modifiers.

    19 

    20 ** public.

    21 

    22  * Public class is visible in other packages.

    23  * Public field is visible everywhere (class must be public too).

    24 

    25 ** private.

    26 

    27  * Private variables or methods may be used only by an instance of the same

    28  class that declares the variable or method

    29  * A private feature may only be accessed by the class that owns the feature.

    30 

    31 ** protected.

    32 

    33  * Is available to all classes in the same package and also available to all

    34  subclasses of the class that owns the protected feature.

    35  * This access is provided even to subclasses that reside in a different

    36  package from the class that owns the protected feature.

    37 

    38 ** default.

    39 

    40 What you get by default ie, without any access modifier.

    41 

    42  * It means that it is visible to all within a particular package.

    43 

    44 * static.

    45 

    46  * Static means one per class, not one for each object no matter how many

    47    instance of a class might exist. This means that you can use them without

    48    creating an instance of a class.

    49  * Static methods are implicitly final, because overriding is done based on

    50    the type of the object, and static methods are attached to a class, not an

    51    object.

    52  * A static method in a superclass can be shadowed by another static method in

    53    a subclass, as long as the original method was not declared final.

    54  * You can't override a static method with a nonstatic method.

    55 

    56 * final.

    57 

    58  * A final class can't be extended ie., final class may not be subclassed.

    59  * A final method can't be overridden when its class is inherited.

    60  * You can't change value of a final variable.

    61 

    62 * Exceptions.

    63 

    64 A checked exception is some subclass of Exception (or Exception itself),

    65 excluding class RuntimeException and its subclasses.

    66 

    67 Unchecked exceptions are RuntimeException and any of its subclasses. Class

    68 Error and its subclasses also are unchecked. With an unchecked exception,

    69 however, the compiler doesn't force client programmers either to catch the

    70 exception or declare it in a throws clause.

    71 

    72 * Inner classes.

    73 

    74 ** Nested top-level classes.

    75 

    76 If you declare a class within a class and specify the static modifier, the

    77 compiler treats the class just like any other top-level class.

    78 

    79 Any class outside the declaring class accesses the nested class with the

    80 declaring class name acting similarly to a package. eg, outer.inner. Top-level

    81 inner classes implicitly have access only to static variables. There can also

    82 be inner interfaces. All of these are of the nested top-level variety.

    83 

    84 ** Member classes.

    85 

    86 Member inner classes are just like other member methods and member variables

    87 and access to the member class is restricted, just like methods and variables.

    88 This means a public member class acts similarly to a nested top-level class.

    89 

    90 The primary difference between member classes and nested top-level classes is

    91 that member classes have access to the specific instance of the enclosing

    92 class.

    93 

    94 ** Local classes.

    95 

    96 Local classes are like local variables, specific to a block of code. Their

    97 visibility is only within the block of their declaration. In order for the

    98 class to be useful beyond the declaration block, it would need to implement a

    99 more publicly available interface.

   100 

   101 Because local classes are not members, the modifiers public, protected,

   102 private, and static are not usable.

   103 

   104 ** Anonymous classes.

   105 

   106 Anonymous inner classes extend local inner classes one level further. As

   107 anonymous classes have no name, you cannot provide a constructor.

   108 

   109 

   110