unused symbol: should not apply to the public constructors of Externalizable classes (IDEA-120639 )

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting7/Externalizable.java

@@ -0,0 +1,36 @@
+import java.io.Externalizable;
+import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
+
+class SerializationProxy implements Externalizable
+{
+  private static final long serialVersionUID = 1L;
+
+  private Object object;
+
+  public SerializationProxy()
+  {
+    // Empty constructor for Externalizable class
+  }
+
+  private <warning descr="Private constructor 'SerializationProxy(java.lang.Object)' is never used">SerializationProxy</warning>(Object object)
+  {
+    this.object = object;
+  }
+
+  public void writeExternal(ObjectOutput out) throws IOException
+  {
+    out.writeObject(this.object);
+  }
+
+  public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
+  {
+    this.object = in.readObject();
+  }
+
+  protected Object readResolve()
+  {
+    return this.object;
+  }
+}