Use of internal classes

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Now that you are ready, you canProgramIn this way. A Java file can contain multiple classes, but only one public class. The class must be an external class, not an internal class. In addition, the method for instantiating inner in test is incorrect. The inner type is always outer. inner, not changed to outer because of outer instantiation. inner, but the compiler has not reported any errors. Written as follows: class Outer {private int size = 10; Class inner {public void dostuff () {system. out. println (++ size) ;}} public class test {public static void main (string [] ARGs) {outer = new outer (); outer. inner inner = outer. new inner (); inner. dostuff ();}}