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  24 .TH "JAVAP" "1" "2018" "JDK 13" "JDK Commands"
  25 .hy
  26 .SH NAME
  27 .PP
  28 javap \- disassemble one or more class files
  29 .SH SYNOPSIS
  30 .PP
  31 \f[CB]javap\f[R] [\f[I]options\f[R]] \f[I]classes\f[R]...
  32 .TP
  33 .B \f[I]options\f[R]
  34 Specifies the command\-line options.
  35 See \f[B]Options for javap\f[R].
  36 .RS
  37 .RE
  38 .TP
  39 .B \f[I]classes\f[R]
  40 Specifies one or more classes separated by spaces to be processed for
  41 annotations.
  42 You can specify a class that can be found in the class path by its file
  43 name, URL, or by its fully qualified class name.
  44 .RS
  45 .PP
  46 Examples:
  47 .RS
  48 .PP
  49 \f[CB]path/to/MyClass.class\f[R]
  50 .RE
  51 .RS
  52 .PP
  53 \f[CB]jar:file:///path/to/MyJar.jar!/mypkg/MyClass.class\f[R]
  54 .RE
  55 .RS
  56 .PP
  57 \f[CB]java.lang.Object\f[R]
  58 .RE
  59 .RE
  60 .SH DESCRIPTION
  61 .PP
  62 The \f[CB]javap\f[R] command disassembles one or more class files.
  63 The output depends on the options used.
  64 When no options are used, the \f[CB]javap\f[R] command prints the
  65 protected and public fields, and methods of the classes passed to it.
  66 .PP
  67 The \f[CB]javap\f[R] command isn\[aq]t multirelease JAR aware.
  68 Using the class path form of the command results in viewing the base
  69 entry in all JAR files, multirelease or not.
  70 Using the URL form, you can use the URL form of an argument to specify a
  71 specific version of a class to be disassembled.
  72 .PP
  73 The \f[CB]javap\f[R] command prints its output to \f[CB]stdout\f[R].
  74 .PP
  75 \f[B]Note:\f[R]
  76 .PP
  77 In tools that support \f[CB]\-\-\f[R] style options, the GNU\-style
  78 options can use the equal sign (\f[CB]=\f[R]) instead of a white space to
  79 separate the name of an option from its value.
  80 .SH OPTIONS FOR JAVAP
  81 .TP
  82 .B \f[CB]\-help\f[R], \f[CB]\-\-help\f[R] , or \f[CB]\-?\f[R]
  83 Prints a help message for the \f[CB]javap\f[R] command.
  84 .RS
  85 .RE
  86 .TP
  87 .B \f[CB]\-version\f[R]
  88 Prints release information.
  89 .RS
  90 .RE
  91 .TP
  92 .B \f[CB]\-verbose\f[R] or \f[CB]\-v\f[R]
  93 Prints additional information about the selected class.
  94 .RS
  95 .RE
  96 .TP
  97 .B \f[CB]\-l\f[R]
  98 Prints line and local variable tables.
  99 .RS
 100 .RE
 101 .TP
 102 .B \f[CB]\-public\f[R]
 103 Shows only public classes and members.
 104 .RS
 105 .RE
 106 .TP
 107 .B \f[CB]\-protected\f[R]
 108 Shows only protected and public classes and members.
 109 .RS
 110 .RE
 111 .TP
 112 .B \f[CB]\-package\f[R]
 113 Shows package/protected/public classes and members (default).
 114 .RS
 115 .RE
 116 .TP
 117 .B \f[CB]\-private\f[R] or \f[CB]\-p\f[R]
 118 Shows all classes and members.
 119 .RS
 120 .RE
 121 .TP
 122 .B \f[CB]\-c\f[R]
 123 Prints disassembled code, for example, the instructions that comprise
 124 the Java bytecodes, for each of the methods in the class.
 125 .RS
 126 .RE
 127 .TP
 128 .B \f[CB]\-s\f[R]
 129 Prints internal type signatures.
 130 .RS
 131 .RE
 132 .TP
 133 .B \f[CB]\-sysinfo\f[R]
 134 Shows system information (path, size, date, MD5 hash) of the class being
 135 processed.
 136 .RS
 137 .RE
 138 .TP
 139 .B \f[CB]\-constants\f[R]
 140 Shows \f[CB]static\ final\f[R] constants.
 141 .RS
 142 .RE
 143 .TP
 144 .B \f[CB]\-\-module\f[R] \f[I]module\f[R] or \f[CB]\-m\f[R] \f[I]module\f[R]
 145 Specifies the module containing classes to be disassembled.
 146 .RS
 147 .RE
 148 .TP
 149 .B \f[CB]\-\-module\-path\f[R] \f[I]path\f[R]
 150 Specifies where to find application modules.
 151 .RS
 152 .RE
 153 .TP
 154 .B \f[CB]\-\-system\f[R] \f[I]jdk\f[R]
 155 Specifies where to find system modules.
 156 .RS
 157 .RE
 158 .TP
 159 .B \f[CB]\-\-class\-path\f[R] \f[I]path\f[R], \f[CB]\-classpath\f[R] \f[I]path\f[R], or \f[CB]\-cp\f[R] \f[I]path\f[R]
 160 Specifies the path that the \f[CB]javap\f[R] command uses to find user
 161 class files.
 162 It overrides the default or the \f[CB]CLASSPATH\f[R] environment variable
 163 when it\[aq]s set.
 164 .RS
 165 .RE
 166 .TP
 167 .B \f[CB]\-bootclasspath\f[R] \f[I]path\f[R]
 168 Overrides the location of bootstrap class files.
 169 .RS
 170 .RE
 171 .TP
 172 .B \f[CB]\-J\f[R]\f[I]option\f[R]
 173 Passes the specified option to the JVM.
 174 For example:
 175 .RS
 176 .IP
 177 .nf
 178 \f[CB]
 179 javap\ \-J\-version
 180 
 181 javap\ \-J\-Djava.security.manager\ \-J\-Djava.security.policy=MyPolicy\ MyClassName
 182 \f[R]
 183 .fi
 184 .PP
 185 See \f[I]Overview of Java Options\f[R] in \f[B]java\f[R].
 186 .RE
 187 .SH JAVAP EXAMPLE
 188 .PP
 189 Compile the following \f[CB]HelloWorldFrame\f[R] class:
 190 .IP
 191 .nf
 192 \f[CB]
 193 import\ java.awt.Graphics;
 194 
 195 import\ javax.swing.JFrame;
 196 import\ javax.swing.JPanel;
 197 
 198 public\ class\ HelloWorldFrame\ extends\ JFrame\ {
 199 
 200 \ \ \ String\ message\ =\ "Hello\ World!";
 201 
 202 \ \ \ public\ HelloWorldFrame(){
 203 \ \ \ \ \ \ \ \ setContentPane(new\ JPanel(){
 204 \ \ \ \ \ \ \ \ \ \ \ \ \@Override
 205 \ \ \ \ \ \ \ \ \ \ \ \ protected\ void\ paintComponent(Graphics\ g)\ {
 206 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ g.drawString(message,\ 15,\ 30);
 207 \ \ \ \ \ \ \ \ \ \ \ \ }
 208 \ \ \ \ \ \ \ \ });
 209 \ \ \ \ \ \ \ \ setSize(100,\ 100);
 210 \ \ \ \ }
 211 \ \ \ \ public\ static\ void\ main(String[]\ args)\ {
 212 \ \ \ \ \ \ \ \ HelloWorldFrame\ frame\ =\ new\ HelloWorldFrame();
 213 \ \ \ \ \ \ \ \ frame.setVisible(true);
 214 
 215 \ \ \ \ }
 216 
 217 }
 218 \f[R]
 219 .fi
 220 .PP
 221 The output from the \f[CB]javap\ HelloWorldFrame.class\f[R] command yields
 222 the following:
 223 .IP
 224 .nf
 225 \f[CB]
 226 Compiled\ from\ "HelloWorldFrame.java"
 227 public\ class\ HelloWorldFrame\ extends\ javax.swing.JFrame\ {
 228 \ \ java.lang.String\ message;
 229 \ \ public\ HelloWorldFrame();
 230 \ \ public\ static\ void\ main(java.lang.String[]);
 231 }
 232 \f[R]
 233 .fi
 234 .PP
 235 The output from the \f[CB]javap\ \-c\ HelloWorldFrame.class\f[R] command
 236 yields the following:
 237 .IP
 238 .nf
 239 \f[CB]
 240 Compiled\ from\ "HelloWorldFrame.java"
 241 public\ class\ HelloWorldFrame\ extends\ javax.swing.JFrame\ {
 242 \ \ java.lang.String\ message;
 243 
 244 \ \ public\ HelloWorldFrame();
 245 \ \ \ \ Code:
 246 \ \ \ \ \ \ \ 0:\ aload_0
 247 \ \ \ \ \ \ \ 1:\ invokespecial\ #1\ \ \ \ \ \ \ \ //\ Method\ javax/swing/JFrame."<init>":()V
 248 \ \ \ \ \ \ \ 4:\ aload_0
 249 \ \ \ \ \ \ \ 5:\ ldc\ \ \ \ \ \ \ \ \ \ \ #2\ \ \ \ \ \ \ \ //\ String\ Hello\ World!
 250 \ \ \ \ \ \ \ 7:\ putfield\ \ \ \ \ \ #3\ \ \ \ \ \ \ \ //\ Field\ message:Ljava/lang/String;
 251 \ \ \ \ \ \ 10:\ aload_0
 252 \ \ \ \ \ \ 11:\ new\ \ \ \ \ \ \ \ \ \ \ #4\ \ \ \ \ \ \ \ //\ class\ HelloWorldFrame$1
 253 \ \ \ \ \ \ 14:\ dup
 254 \ \ \ \ \ \ 15:\ aload_0
 255 \ \ \ \ \ \ 16:\ invokespecial\ #5\ \ \ \ \ \ \ \ //\ Method\ HelloWorldFrame$1."<init>":(LHelloWorldFrame;)V
 256 \ \ \ \ \ \ 19:\ invokevirtual\ #6\ \ \ \ \ \ \ \ //\ Method\ setContentPane:(Ljava/awt/Container;)V
 257 \ \ \ \ \ \ 22:\ aload_0
 258 \ \ \ \ \ \ 23:\ bipush\ \ \ \ \ \ \ \ 100
 259 \ \ \ \ \ \ 25:\ bipush\ \ \ \ \ \ \ \ 100
 260 \ \ \ \ \ \ 27:\ invokevirtual\ #7\ \ \ \ \ \ \ \ //\ Method\ setSize:(II)V
 261 \ \ \ \ \ \ 30:\ return
 262 
 263 \ \ public\ static\ void\ main(java.lang.String[]);
 264 \ \ \ \ Code:
 265 \ \ \ \ \ \ \ 0:\ new\ \ \ \ \ \ \ \ \ \ \ #8\ \ \ \ \ \ \ \ //\ class\ HelloWorldFrame
 266 \ \ \ \ \ \ \ 3:\ dup
 267 \ \ \ \ \ \ \ 4:\ invokespecial\ #9\ \ \ \ \ \ \ \ //\ Method\ "<init>":()V
 268 \ \ \ \ \ \ \ 7:\ astore_1
 269 \ \ \ \ \ \ \ 8:\ aload_1
 270 \ \ \ \ \ \ \ 9:\ iconst_1
 271 \ \ \ \ \ \ 10:\ invokevirtual\ #10\ \ \ \ \ \ \ //\ Method\ setVisible:(Z)V
 272 \ \ \ \ \ \ 13:\ return
 273 }
 274 \f[R]
 275 .fi