Java

Array key point: Not scalable, once constructed length cannot be change, When construct numeric primitive type, it will filled with default value. byte, short, int, long, double, float 0 char filled with empty. boolean filled with false. object filled with

Using scanner read user password from terminal isn’t practical due to sensitive data. Alternatively we can use Console class. Note! This program can be only execute from the terminal, it will not work in the IDE run java program.

InputStream in read user input from terminal bytes by bytes. We can use the Scanner class to read the whole string. To read integer, try enter any single digit from 0 – 9, What if you allow to enter more

This post will cover the following topics in this article Concatenation Performance comparison String Join Substring String Immutable String Pool and equality String compareTo Concatenation Plus operator, when 2 string are use with plus operator, string will be combine. Java

Primitive type compare using == , while object compare using equals method. When compare object with ==, we’re compare the reference (memory location) Integer Integer and Long type wrapper will always cache values in the range -128 to 127. If

This topic will discuss about incremental operation in Java. ++addFirst yield value increment before it used while addLater++ yield value before increment. These are know as pre-increment and post-increment. Another example Tricky question 1, what is the output? Keep in

This topic will talk about what is wrapper types, boxing, unboxing and autoboxing. A wrapper type is a class that encapsulates types. boolean => Boolean byte => Byte short => Short int = Integer long => Long float => Float

The simplest types in java are call primitive type. Java has 8 built-in primitive types, and each of these has default value when not declare in a method. boolean, 8-bits, default false byte, 8-bits default 0 short, 16-bits default 0

To format Java 8 LocalDate, LocalTime or LocalDateTime. We can use DateTimeFormatter. Month Output Day Output Year Output Day Of Month Quarter of Year AM/PM LocalizedDate, LocalizedTime & LocalizeDateTime – FormatStyle.SHORT LocalizedDate, LocalizedTime & LocalizeDateTime – FormatStyle.MEDIUM LocalizedDate, LocalizedTime &