Java learning memo (data type)

Since I started studying Java Silver, I will upload it as my memorandum. Since it is a rough memo, details are not described.

Chapter 2 Java Data Type Manipulation   1.2. Data type ・ Primitive type Handles numbers such as integers and floating point numbers, boolean values, and characters.    type)  boolean:true,false  Char: 16bit Unicode characters \ u0000 ~ \ uFFFF byte: 8-bit integer -128 to 127 short: 16bit integer -32768 to 32767 Int: 32bit integer-2147483648 ~ 2147483647 Long: 64-bit integer Float: 32-bit single precision floating point number Double: 64-bit double precision floating point number   ・ Reference type Object type, array type, enumeration type.   3. 3. Numeric literal ・ How to use underscore "_" Improves the visibility of numeric literals with many digits. (1) Cannot be described at the beginning and end of literals (2) Cannot be written before or after the symbol ("." "L" "F" "0b" "0x" etc ..)

  1. identifier ・ Reserved words cannot be used ・ Only "_" and currency symbols are used ・ Don't start with numbers

  2. Method call -Method defined in the same instance: Method name (argument) -For the method defined in the instance: Variable. Method name (argument) -For static methods: class name.method name (argument)

  3. Garbage collection The garbage collector looks for obsolete instances in memory, destroys them, and frees memory.

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