1. The number that an int can represent is more than 2 billion

  2. In a JVM compliant virtual machine, Boolean alone will call int-related instructions, so 4 bytes, and Booean array will call byte[] related instructions, all 1 byte.

  3. Char byte short int String enmu from jdk8

  4. Math.round(-11.5) returns -11. Rounding works by adding 0.5 to a parameter and rounding it down.

  5. short s1 = 1; s1 = s1 + 1; Short s1 = 1; s1 += 1; Compiling error, += will automatically perform precision conversion

  6. Single-line comments can be nested multi-line comments and document comments cannot be nested

  7. Of the four access modifiers, private and protected do not modify classes and interfaces; public and default do

  8. Goto is a reserved word in Java that is not used in the current version of Java