Converter tests:

Change test data files extension to "java"

j2k/tests/testData/ast/constructors/customerBuilder.java

@@ -0,0 +1,55 @@
+//file
+package org.test.customer
+
+class Customer {
+  public final String _firstName;
+  public final String _lastName;
+
+  Customer(String first, String last) {
+    doSmthBefore();
+    _firstName = first;
+    _lastName = last;
+    doSmthAfter();
+  }
+
+  public String getFirstName() {
+    return _firstName;
+  }
+
+  public String getLastName() {
+    return _lastName;
+  }
+
+  private void doSmthBefore() {}
+  private void doSmthAfter() {}
+}
+
+class CustomerBuilder {
+  public String _firstName = "Homer";
+  public String _lastName = "Simpson";
+
+  public CustomerBuilder WithFirstName(String firstName) {
+    _firstName = firstName;
+    return this;
+  }
+
+  public CustomerBuilder WithLastName(String lastName) {
+    _lastName = lastName;
+    return this;
+  }
+
+  public Customer Build() {
+    return new Customer(_firstName, _lastName);
+  }
+}
+
+public class User {
+  public static void main(Array[String] args) {
+     Customer customer = new CustomerBuilder()
+       .WithFirstName("Homer")
+       .WithLastName("Simpson")
+       .Build();
+     System.out.println(customer.getFirstName());
+     System.out.println(customer.getLastName());
+  }
+}