The Java
®
Language Specification
4.2 Primitive Types and Values 52
4.2.1 Integral Types and Values 53
4.2.2 Integer Operations 53
4.2.3 Floating-Point Types, Formats, and Values 55
4.2.4 Floating-Point Operations 58
4.2.5 The boolean Type and boolean Values 62
4.3 Reference Types and Values 63
4.3.1 Objects 64
4.3.2 The Class Object 67
4.3.3 The Class String 67
4.3.4 When Reference Types Are the Same 68
4.4 Type Variables 68
4.5 Parameterized Types 70
4.5.1 Type Arguments of Parameterized Types 71
4.5.2 Members and Constructors of Parameterized Types 74
4.6 Type Erasure 75
4.7 Reifiable Types 76
4.8 Raw Types 77
4.9 Intersection Types 81
4.10 Subtyping 82
4.10.1 Subtyping among Primitive Types 82
4.10.2 Subtyping among Class and Interface Types 83
4.10.3 Subtyping among Array Types 84
4.10.4 Least Upper Bound 84
4.10.5 Type Projections 87
4.11 Where Types Are Used 89
4.12 Variables 94
4.12.1 Variables of Primitive Type 95
4.12.2 Variables of Reference Type 95
4.12.3 Kinds of Variables 97
4.12.4 final Variables 99
4.12.5 Initial Values of Variables 101
4.12.6 Types, Classes, and Interfaces 102
5
Conversions and Contexts 105
5.1 Kinds of Conversion 108
5.1.1 Identity Conversion 108
5.1.2 Widening Primitive Conversion 108
5.1.3 Narrowing Primitive Conversion 110
5.1.4 Widening and Narrowing Primitive Conversion 113
5.1.5 Widening Reference Conversion 113
5.1.6 Narrowing Reference Conversion 113
5.1.6.1 Allowed Narrowing Reference Conversion 114
5.1.6.2 Checked and Unchecked Narrowing Reference
Conversions 115
5.1.6.3 Narrowing Reference Conversions at Run Time 116
5.1.7 Boxing Conversion 119
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