Number
is a superclass of Wrapper classes ( Integer, Double,Float…)
Boxing vs Unboxing
Boxing: is converting a primitive data type to an object (example from int to Integer).
Unboxing:opposite of boxing
some methods of Number class
valueOf(),parseInt(),toString(),equals(), compareTo(),min(),max()…
Boolean
true or false
some Character methods
hashCode(),isLetter(),isDigit(),isWhitespace(), toUpperCase()…
Array
a data structure which is fixed-size and store elements of the same data type.
Example of passing an array as argument to a method
printArray(new int[]{1,2,5,3,9,11});
Some Arrays method
*binarySearch()
*equals()
*fill()
*sort()
Some Math class methods
max(),min(),abs(),sqrt()…