<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have searched the <a href="https://github.com/apache/dubbo/issues">issues</a> of this repository and believe that this is not a duplicate.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have checked the <a href="https://github.com/apache/dubbo/blob/master/FAQ.md">FAQ</a> of this repository and believe that this is not a duplicate.</li>
</ul>
<h3 dir="auto">Environment</h3>
<ul dir="auto">
<li>Dubbo version: 2.7.3-SNAPSHOT</li>
<li>Operating System version:mac os 10.13.6</li>
<li>Java version: 1.8.0_171</li>
</ul>
<h3 dir="auto">Steps to reproduce this issue</h3>
<ol dir="auto">
<li>export an dubbo service which has a method with an collection argument</li>
</ol>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="    @Override
    public String testListName(List&lt;String&gt; list) {
        return list.toString();
    }"><pre class="notranslate"><code class="notranslate">    @Override
    public String testListName(List&lt;String&gt; list) {
        return list.toString();
    }
</code></pre></div>
<ol start="2" dir="auto">
<li>start a telnet invoke or generic call to invoke the service<br>
<code class="notranslate">dubbo&gt;invoke testListName(["a","b",null])</code></li>
</ol>
<p dir="auto">Pls. provide [GitHub address] to reproduce this issue.</p>
<h3 dir="auto">Expected Result</h3>
<p dir="auto">What do you expected from the above steps？</p>
<p dir="auto"><code class="notranslate">result: "[a, b, null]"</code></p>
<h3 dir="auto">Actual Result</h3>
<p dir="auto">What actually happens?</p>
<p dir="auto">throw an NPE when pojoUtils invoke method #realize0</p>
<p dir="auto">If there is an exception, please attach the exception trace:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="Failed to invoke method testListName, cause: java.lang.NullPointerException
java.lang.NullPointerException
	at org.apache.dubbo.common.utils.PojoUtils.realize0(PojoUtils.java:369)
	at org.apache.dubbo.common.utils.PojoUtils.realize(PojoUtils.java:205)
	at org.apache.dubbo.common.utils.PojoUtils.realize(PojoUtils.java:95)
	at org.apache.dubbo.rpc.protocol.dubbo.telnet.InvokeTelnetHandler.telnet(InvokeTelnetHandler.java:125)
	at org.apache.dubbo.remoting.telnet.support.TelnetHandlerAdapter.telnet(TelnetHandlerAdapter.java:59)
	at org.apache.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.received(HeaderExchangeHandler.java:205)
	at org.apache.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:51)
	at org.apache.dubbo.remoting.transport.dispatcher.ChannelEventRunnable.run(ChannelEventRunnable.java:57)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)"><pre class="notranslate"><code class="notranslate">Failed to invoke method testListName, cause: java.lang.NullPointerException
java.lang.NullPointerException
	at org.apache.dubbo.common.utils.PojoUtils.realize0(PojoUtils.java:369)
	at org.apache.dubbo.common.utils.PojoUtils.realize(PojoUtils.java:205)
	at org.apache.dubbo.common.utils.PojoUtils.realize(PojoUtils.java:95)
	at org.apache.dubbo.rpc.protocol.dubbo.telnet.InvokeTelnetHandler.telnet(InvokeTelnetHandler.java:125)
	at org.apache.dubbo.remoting.telnet.support.TelnetHandlerAdapter.telnet(TelnetHandlerAdapter.java:59)
	at org.apache.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.received(HeaderExchangeHandler.java:205)
	at org.apache.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:51)
	at org.apache.dubbo.remoting.transport.dispatcher.ChannelEventRunnable.run(ChannelEventRunnable.java:57)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
</code></pre></div>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have searched the <a href="https://github.com/apache/dubbo/issues">issues</a> of this repository and believe that this is not a duplicate.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have checked the <a href="https://github.com/apache/dubbo/blob/master/FAQ.md">FAQ</a> of this repository and believe that this is not a duplicate.</li>
</ul>
<h3 dir="auto">Environment</h3>
<ul dir="auto">
<li>Dubbo version: xxx</li>
<li>Operating System version: xxx</li>
<li>Java version: xxx</li>
</ul>
<h3 dir="auto">Steps to reproduce this issue</h3>
<ol dir="auto">
<li>xxx</li>
<li>xxx</li>
<li>xxx</li>
</ol>
<p dir="auto">Pls. provide [GitHub address] to reproduce this issue.</p>
<h3 dir="auto">Expected Result</h3>
<p dir="auto">What do you expected from the above steps？</p>
<h3 dir="auto">Actual Result</h3>
<p dir="auto">What actually happens?</p>
<p dir="auto">If there is an exception, please attach the exception trace:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="Just put your stack trace here!"><pre class="notranslate"><code class="notranslate">Just put your stack trace here!
</code></pre></div>