</script><metaname="aes-config"content="pid=xux-opensource&user_type=101&uid=&username=&dim10=arthas"><scriptsrc="//g.alicdn.com/alilog/mlog/aplus_v2.js"id="beacon-aplus"exparams="clog=o&aplus&sidx=aplusSidx&ckx=aplusCkx"></script><scriptsrc="//g.alicdn.com/aes/??tracker/1.0.34/index.js,tracker-plugin-pv/2.4.5/index.js,tracker-plugin-event/1.2.5/index.js,tracker-plugin-jserror/1.0.13/index.js,tracker-plugin-api/1.1.14/index.js,tracker-plugin-perf/1.1.8/index.js,tracker-plugin-eventTiming/1.0.4/index.js"></script><title>Fundamental Fields in Expressions | arthas</title><metaname="description"content="arthas user document">
</code></pre><divclass="line-numbers"aria-hidden="true"><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div><divclass="line-number"></div></div></div><p>Description for the variables in the class <code>Advice</code>:</p><table><thead><tr><thstyle="text-align:right;">Name</th><thstyle="text-align:left;">Specification</th></tr></thead><tbody><tr><tdstyle="text-align:right;">loader</td><tdstyle="text-align:left;">the class loader for the current called class</td></tr><tr><tdstyle="text-align:right;">clazz</td><tdstyle="text-align:left;">the reference to the current called class</td></tr><tr><tdstyle="text-align:right;">method</td><tdstyle="text-align:left;">the reference to the current called method</td></tr><tr><tdstyle="text-align:right;">target</td><tdstyle="text-align:left;">the instance of the current called class</td></tr><tr><tdstyle="text-align:right;">params</td><tdstyle="text-align:left;">the parameters for the current call, which is an array (when there's no parameter, it will be an empty array)</td></tr><tr><tdstyle="text-align:right;">returnObj</td><tdstyle="text-align:left;">the return value from the current call - only available when the method call returns normally (<code>isReturn==true</code>), and <code>null</code> is for <code>void</code> return value</td></tr><tr><tdstyle="text-align:right;">throwExp</td><tdstyle="text-align:left;">the exceptions thrown from the current call - only available when the method call throws exception (<code>isThrow==true</code>)</td></tr><tr><tdstyle="text-align:right;">isBefore</td><tdstyle="text-align:left;">flag to indicate the method is about to execute. <code>isBefore==true</code> but <code>isThrow==false</code> and <code>isReturn==false</code> since it's no way to know how the method call will end</td></tr><tr><tdstyle="text-align:right;">isThrow</td><tdstyle="text-align:left;">flag to indicate the method call ends with exception thrown</td></tr><tr><tdstyle="text-align:right;">isReturn</td><tdstyle="text-align:left;">flag to indicate the method call ends normally without exception thrown</td></tr></tbody></table><p>All variables listed above can be used directly in the <ahref="https://commons.apache.org/dormant/commons-ognl/language-guide.html"target="_blank"rel="noopener noreferrer">OGNL expression<span><svgclass="external-link-icon"xmlns="http://www.w3.org/2000/svg"aria-hidden="true"focusable="false"x="0px"y="0px"viewbox="0 0 100 100"width="15"height="15"><pathfill="currentColor"d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygonfill="currentColor"points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><spanclass="external-link-icon-sr-only">open in new window</span></span></a>. The command will not execute and exit if there's illegal OGNL grammar or unexpected variable in the expression.</p><ul><li><ahref="https://github.com/alibaba/arthas/issues/71"target="_blank"rel="noopener noreferrer">typical use cases<span><svgclass="external-link-icon"xmlns="http://www.w3.org/2000/svg"aria-hidden="true"focusable="false"x="0px"y="0px"viewbox="0 0 100 100"width="15"height="15"><pathfill="currentColor"d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygonfill="currentColor"points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><spanclass="external-link-icon-sr-only">open in new window</span></span></a>;</li><li><ahref="https://commons.apache.org/dorman
