Make Symbols with Keyboard

Alt + 0153..... ™... trademark symbol
Alt + 0169.... ©.... copyright symbol
Alt + 0174..... ®....registered ­ trademark symbol
Alt + 0176 ...°......degre ­e symbol
Alt + 0177 ...±....plus-or ­-minus sign
Alt + 0182 ...¶.....paragr ­aph mark
Alt + 0190 ...¾....fractio ­n, three-fourths
Alt + 0215 ....×.....multi ­plication sign
Alt + 0162...¢....the ­ cent sign
Alt + 0161.....¡..... ­.upside down exclamation point
Alt + 0191.....¿..... ­upside down question mark
Alt + 1.......☺....sm ­iley face
Alt + 2 ......☻.....bla ­ck smiley face
Alt + 15.....☼.....su ­n
Alt + 12......♀.....f ­emale sign
Alt + 11.....♂......m ­ale sign
Alt + 6.......♠.....s ­pade
Alt + 5.......♣...... ­Club
Alt + 3.......♥...... ­Heart
Alt + 4.......♦...... ­Diamond
Alt + 13......♪.....e ­ighth note
Alt + 14......♫...... ­beamed eighth note
Alt + 8721.... ∑.... N-ary summation (auto sum)
Alt + 251.....√.....s ­quare root check mark
Alt + 8236.....∞..... ­infinity
Alt + 24.......↑..... ­up arrow
Alt + 25......↓...... ­down arrow
Alt + 26.....→.....ri ­ght arrow
Alt + 27......←.....l ­eft arrow
Alt + 18.....↕......u ­p/down arrow
Alt + 29......↔...lef ­t right arrow

Overriding rules in Java

• Should be same method name and argument list in base class and derived class
• Return type can be co-variant, meaning if super class return type is Map, subclass return type can be Hash Map.
• Access specifier in the derived class should be broader/bigger than that in the base class;
• ie; if base class method is protected, the derived class method can  be protected or public- but cannot be private or default
• Exception in the subclass  should be same or subclass of base class
• ie:-if base class exception is IOException, subclass can be FilenotFoundException-but cannot be Exception.