Assigning a value of one type to a variable of another type is known as Type Casting. In Java, type casting is classified into two types,

Widening or Automatic type conversion: Automatic Type casting take place when, the two types are compatible and the target type is larger than the source type.
Narrowing or Explicit type conversion:When you are assigning a larger type value to a variable of smaller type, then you need to perform explicit type casting.
Working Flow chart

Different Cases of Explicitly and Implicit
Case 1:
byte a=10; int b; b=a;
All Statement is true.
Case 2:
int a=10; byte b; b=a;/*Thread Line is not compile, Error is possible loss of precision*/
Thread Line is not compile, Error is possible loss of precision.
Case 3:
int a=10; byte b; b=a; /*Thread Line is not compile, Error is possible loss of precision */ b=(byte)a;/*Forth Line is compile and run*/
Thread Line is not compile, Error is possible loss of precision.
Forth Line is compile and run.
Case 4:
short a=10; int b; b=a;
All Statement is true.
Case 5:
int a=10; short b; b=a; /*Thread Line is not compile, Error is possible loss of precision */ b=(short)a;/*Forth Line is compile and run*/
Thread Line is not compile, Error is possible loss of precision.
Forth Line is compile and run.
Case 6:
int a=32768; short b; b=a; /*Thread Line is not compile, Error is possible loss of precision */ b=(short)a;/*Forth Line is compile and run*/
Thread Line is not compile, Error is possible loss of precision.
Forth Line is compile and run.
Case 7:
byte a=10; char ch; ch=a; /*Thread Line is not compile, Error is possible loss of precision */ ch=(char)a;/*Forth Line is compile and run*/
Thread Line is not compile, Error is possible loss of precision.
Forth Line is compile and run.
Case 8:
char ch='A'; byte b; b=ch; /*Thread Line is not compile, Error is possible loss of precision */ b=(byte)ch;/*Forth Line is compile and run*/
Thread Line is not compile, Error is possible loss of precision
Forth Line is compile and run
Case 9:
short a=10; char ch; ch=a; /*Thread Line is not compile, Error is possible loss of precision */ ch=(char)a;/*Forth Line is compile and run*/
Thread Line is not compile, Error is possible loss of precision
Forth Line is compile and run
Case 10:
char ch='A'; short s; s=ch; /*Thread Line is not compile, Error is possible loss of precision */ s=(short)ch;/*Forth Line is compile and run*/
Thread Line is not compile, Error is possible loss of precision.
Forth Line is compile and run.
Case 11:
int a=10; char ch; ch=a; /*Thread Line is not compile, Error is possible loss of precision */ ch=(char)a;/*Forth Line is compile and run*/
Thread Line is not compile, Error is possible loss of precision.
Forth Line is compile and run.
Case 12:
char ch='A'; int b; b=ch;
All Statement is true.
Case 13:
int a=10; long b; b=a;
All Statement is true.
Case 14:
long a=10; int b; b=a; /*Thread Line is not compile, Error is possible loss of precision */ b=(int)a;/*Forth Line is compile and run*/
Thread Line is not compile, Error is possible loss of precision.
Forth Line is compile and run.
etc......