Andy McFadden | aa33602 | 2009-04-27 13:19:51 -0700 | [diff] [blame] | 1 | <html> |
| 2 | <head> |
| 3 | <title>Basic Dalvik VM Invocation</title> |
| 4 | </head> |
| 5 | |
| 6 | <body> |
| 7 | <h1>Basic Dalvik VM Invocation</h1> |
| 8 | |
| 9 | <p> |
| 10 | On an Android device, the Dalvik virtual machine usually executes embedded |
| 11 | in the Android application framework. It's also possible to run it directly, |
| 12 | just as you would a virtual machine on your desktop system. |
| 13 | </p><p> |
| 14 | After compiling your Java language sources, convert and combine the .class |
| 15 | files into a DEX file, and push that to the device. Here's a simple example: |
| 16 | |
| 17 | </p><p><code> |
| 18 | % <font color="green">echo 'class Foo {'\</font><br> |
| 19 | > <font color="green">'public static void main(String[] args) {'\</font><br> |
| 20 | > <font color="green">'System.out.println("Hello, world"); }}' > Foo.java</font><br> |
| 21 | % <font color="green">javac Foo.java</font><br> |
| 22 | % <font color="green">dx --dex --output=foo.jar Foo.class</font><br> |
| 23 | % <font color="green">adb push foo.jar /sdcard</font><br> |
| 24 | % <font color="green">adb shell dalvikvm -cp /sdcard/foo.jar Foo</font><br> |
Carl Shapiro | de75089 | 2010-06-08 16:37:12 -0700 | [diff] [blame] | 25 | Hello, world |
Andy McFadden | aa33602 | 2009-04-27 13:19:51 -0700 | [diff] [blame] | 26 | </code> |
| 27 | </p><p> |
| 28 | The <code>-cp</code> option sets the classpath. The initial directory |
| 29 | for <code>adb shell</code> may not be what you expect it to be, so it's |
| 30 | usually best to specify absolute pathnames. |
| 31 | |
| 32 | </p><p> |
| 33 | The <code>dx</code> command accepts lists of individual class files, |
| 34 | directories, or Jar archives. When the <code>--output</code> filename |
| 35 | ends with <code>.jar</code>, <code>.zip</code>, or <code>.apk</code>, |
| 36 | a file called <code>classes.dex</code> is created and stored inside the |
| 37 | archive. |
| 38 | </p><p> |
| 39 | Run <code>adb shell dalvikvm -help</code> to see a list of command-line |
| 40 | options. |
| 41 | </p><p> |
| 42 | |
| 43 | |
| 44 | |
Andy McFadden | c7659ec | 2009-09-18 16:14:41 -0700 | [diff] [blame] | 45 | <h2>Using a debugger</h2> |
| 46 | |
| 47 | <p> |
| 48 | You can debug stand-alone applications with any JDWP-compliant debugger. |
| 49 | There are two basic approaches. |
| 50 | </p><p> |
| 51 | The first way is to connect directly through TCP. Add, to the "dalvikvm" |
| 52 | invocation line above, an argument like: |
| 53 | </p><p> |
| 54 | <code> -agentlib:jdwp=transport=dt_socket,address=8000,server=y,suspend=y</code> |
| 55 | </p><p> |
| 56 | This tells the VM to wait for a debugger to connect to it on TCP port 8000. |
| 57 | You need to tell adb to forward local port 8000 to device port 8000: |
| 58 | </p><p> |
| 59 | <code>% <font color="green">adb forward tcp:8000 tcp:8000</font></code> |
| 60 | </p><p> |
| 61 | and then connect to it with your favorite debugger (using <code>jdb</code> |
| 62 | as an example here): |
| 63 | </p><p> |
| 64 | <code>% <font color="green">jdb -attach localhost:8000</font></code> |
| 65 | </p><p> |
| 66 | When the debugger attaches, the VM will be in a suspended state. You can |
| 67 | set breakpoints and then tell it to continue. |
| 68 | |
| 69 | |
| 70 | </p><p> |
| 71 | You can also connect through DDMS, like you would for an Android application. |
| 72 | Add, to the "dalvikvm" command line: |
| 73 | </p><p> |
| 74 | <code> -agentlib:jdwp=transport=dt_android_adb,suspend=y,server=y</code> |
| 75 | </p><p> |
| 76 | Note the <code>transport</code> has changed, and you no longer need to |
| 77 | specify a TCP port number. When your application starts, it will appear |
| 78 | in DDMS, with "?" as the application name. Select it in DDMS, and connect |
| 79 | to it as usual, e.g.: |
| 80 | </p><p> |
| 81 | <code>% <font color="green">jdb -attach localhost:8700</font></code> |
| 82 | </p><p> |
| 83 | Because command-line applications don't include the client-side |
| 84 | DDM setup, features like thread monitoring and allocation tracking will not |
| 85 | be available in DDMS. It's strictly a debugger pass-through in this mode. |
| 86 | </p><p> |
| 87 | See <a href="debugger.html">Dalvik Debugger Support</a> for more information |
| 88 | about using debuggers with Dalvik. |
| 89 | |
| 90 | |
| 91 | |
Andy McFadden | aa33602 | 2009-04-27 13:19:51 -0700 | [diff] [blame] | 92 | <h2>Working with the desktop build</h2> |
| 93 | |
| 94 | <!-- largely lifted from |
| 95 | http://groups.google.com/group/android-porting/browse_thread/thread/ab553116dbc960da/29167c58b3b49051#29167c58b3b49051 |
| 96 | --> |
| 97 | |
| 98 | <p> |
| 99 | The Dalvik VM can also be used directly on the desktop. This is somewhat |
| 100 | more complicated however, because you won't have certain things set up in |
| 101 | your environment, and several native code libraries are required to support |
| 102 | the core Dalvik libs. |
| 103 | </p><p> |
| 104 | Start with: |
| 105 | |
| 106 | <pre> |
| 107 | . build/envsetup.sh |
| 108 | lunch sim-eng |
| 109 | </pre> |
| 110 | |
| 111 | You should see something like: |
| 112 | |
| 113 | <pre> |
| 114 | ============================================ |
| 115 | TARGET_PRODUCT=sim |
| 116 | TARGET_BUILD_VARIANT=eng |
| 117 | TARGET_SIMULATOR=true |
| 118 | TARGET_BUILD_TYPE=debug |
| 119 | TARGET_ARCH=x86 |
| 120 | HOST_ARCH=x86 |
| 121 | HOST_OS=linux |
| 122 | HOST_BUILD_TYPE=release |
| 123 | BUILD_ID= |
| 124 | ============================================ |
| 125 | </pre> |
| 126 | |
| 127 | </p></p> |
| 128 | This configures you to build for the desktop, linking against glibc. |
| 129 | This mode is NOT recommended for anything but experimental use. It |
| 130 | may go away in the future. |
| 131 | </p></p> |
| 132 | You may see <code>TARGET_BUILD_TYPE=release</code> or <code>=debug</code> |
| 133 | or possibly nothing there at all. You may want to replace the |
| 134 | <code>lunch</code> command with |
| 135 | <code>choosecombo Simulator debug sim eng</code>. |
| 136 | </p></p> |
| 137 | Build the world (add a <code>-j4</code> if you have multiple cores): |
| 138 | |
| 139 | <pre> |
| 140 | make |
| 141 | </pre> |
| 142 | |
| 143 | </p></p> |
| 144 | When that completes, you have a working dalvikm on your desktop |
| 145 | machine: |
| 146 | |
| 147 | <pre> |
| 148 | % dalvikvm |
| 149 | E/dalvikvm(19521): ERROR: must specify non-'.' bootclasspath |
| 150 | W/dalvikvm(19521): JNI_CreateJavaVM failed |
| 151 | Dalvik VM init failed (check log file) |
| 152 | </pre> |
| 153 | |
| 154 | </p></p> |
| 155 | To actually do something, you need to specify the bootstrap class path |
| 156 | and give it a place to put DEX data that it uncompresses from jar |
| 157 | files. You can do that with a script like this: |
| 158 | |
| 159 | <blockquote><pre> |
| 160 | #!/bin/sh |
| 161 | |
| 162 | # base directory, at top of source tree; replace with absolute path |
| 163 | base=`pwd` |
| 164 | |
| 165 | # configure root dir of interesting stuff |
| 166 | root=$base/out/debug/host/linux-x86/product/sim/system |
| 167 | export ANDROID_ROOT=$root |
| 168 | |
| 169 | # configure bootclasspath |
| 170 | bootpath=$root/framework |
| 171 | export BOOTCLASSPATH=$bootpath/core.jar:$bootpath/ext.jar:$bootpath/framework.jar:$bootpath/android.policy.jar:$bootpath/services.jar |
| 172 | |
| 173 | # this is where we create the dalvik-cache directory; make sure it exists |
| 174 | export ANDROID_DATA=/tmp/dalvik_$USER |
| 175 | mkdir -p $ANDROID_DATA/dalvik-cache |
| 176 | |
| 177 | exec dalvikvm $@ |
| 178 | </pre></blockquote> |
| 179 | |
| 180 | </p></p> |
| 181 | The preparation with <code>dx</code> is the same as before: |
| 182 | |
| 183 | <pre> |
| 184 | % cat > Foo.java |
| 185 | class Foo { public static void main(String[] args) { |
| 186 | System.out.println("Hello, world"); |
| 187 | } } |
| 188 | (ctrl-D) |
| 189 | % javac Foo.java |
| 190 | % dx --dex --output=foo.jar Foo.class |
| 191 | % ./rund -cp foo.jar Foo |
| 192 | Hello, world |
| 193 | </pre> |
| 194 | |
| 195 | As above, you can get some info about valid arguments like this: |
| 196 | |
| 197 | <pre> |
| 198 | % ./rund -help |
| 199 | </pre> |
| 200 | |
| 201 | </p></p> |
| 202 | This also shows what options the VM was configured with. The sim "debug" |
| 203 | build has all sorts of additional assertions and checks enabled, |
| 204 | which slows the VM down, but since this is just for experiments it |
| 205 | doesn't matter. |
| 206 | |
| 207 | </p></p> |
| 208 | All of the above applies to x86 Linux. Anything else will likely |
| 209 | require a porting effort. If libffi supports your system, the amount of |
| 210 | work required should be minor. |
| 211 | |
Andy McFadden | 842e20c | 2009-04-30 14:12:27 -0700 | [diff] [blame] | 212 | </p></p> |
| 213 | <address>Copyright © 2009 The Android Open Source Project</address> |
| 214 | |
Andy McFadden | aa33602 | 2009-04-27 13:19:51 -0700 | [diff] [blame] | 215 | </body> |
| 216 | </html> |