title: rJava - .jcall calling issue: method with signature not found
body: <p>I am trying to call a method in java class with rJava for a few days and I did not yet figure it out what I am doing wrong. Maybe someone here will have a some clues for me.</p>
  
  <p>The situation looks like this:</p>
  
  <ol>
  <li><p>I load library and initializing an object (that's works fine):</p>
  
  <pre><code>library(rJava)
  .jinit('C:/javatemp/worker.jar') 
  jobject &lt;- .jnew("worker.concrete")
  </code></pre></li>
  <li><p>I list methods and I get fine result:</p>
  
  <pre><code>.jmethods(jobject)
  &gt;  [1] "public java.util.List worker.concrete.lookup(java.lang.CharSequence)"  
  </code></pre></li>
  <li><p>I am preparing input structure which also works fine:</p>
  
  <pre><code>word &lt;- .jnew("java/lang/String", "a word")
  input = .jcast(word, "java/lang/CharSequence", check = TRUE)
  </code></pre></li>
  <li><p>However when I am trying to execute the method I get an error that such method does not exist...</p>
  
  <pre><code>out = .jcall(jobject,"Ljava/util/List","lookup",input)
  &gt; Error in .jcall(jobject, "Ljava/util/List", "lookup", input) : 
  method lookup with signature (Ljava/lang/CharSequence;)Ljava/util/List not found
  </code></pre></li>
  </ol>
  
  <p>Does anyone have an idea how to call such method? </p>