The Java compiler (javac) translates Java source code into Java
???bytecode,??? which is a platform-independent intermediate code. When the Java program (java) runs, the Java
Virtual Machine (JVM) interprets the Java bytecode.
A virtual machine such as the Java JVM is a computer defined by software rather than hardware. A virtual
machine runs programs like a real computer, but the virtual machine is really another program, a construction in
software, that fetches, decodes, and executes the program??™s instructions. The instructions are referred to as bytecode.
In the case of Java, the JVM implements a machine described by the official JVM specification by
Lindholm and Yellin, which you can view on the Sun Microsystems website: http://java.sun.com/docs/
books/vmspec/.
The Java Virtual Machine is the cornerstone of the Java and Java 2 platforms. It is the component of the technology
responsible for its hardware and operating system independence, the small size of its compiled code, and its ability
to protect users from malicious programs.
The Java Virtual Machine is an abstract computing machine. Like a real computing machine, it has an instruction
set and manipulates various memory areas at run time.
Pages:
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142