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1. Top results related to can a java subclass inherit more than one interface error

   • Can a class be subclass of more than one class?

     Top Answer

     Answered Apr 11, 2014 · 3 votes

     What you are asking for is multiple inheritance. Java does not support this.

     Multiple inheritance is hard for compiler writers to implement - mainly because of the diamond problem.

     Except - in Java 8 there are interfaces with default methods. This allows sort of a light-weight version of multiple inheritance.

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     1/5

   • Can a java enum have more than one constructor?

     Top Answer

     Answered Aug 07, 2017 · 17 votes

     public enum MyEnum { ONE(1), TWO(1, 2); private int value1, value2;- private MyEnum(int value) { this.value1 = value; this.value2 = 0; // default // this.value2 = getFromSomewhereElse(); // get it at runtime } private MyEnum(int value1, int value2) { this.value1 = value1; this.value2 = value2; } public int getValue1() { return this.value1; } public int getValue2() { return this.value2; }}

     • Yes, you must declare the enum values at the start. Always.
     • See code above. It is possible. If people do it depends on the application. If you have a lot of fields and most of them should be a default value, it is a good thing to use multiple constructors. Also, the values for the fields could be read at runtime (from a file or another static class).

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     2/5

   • Can a java file have more than one class?

     Top Answer

     Answered Jan 12, 2017 · 148 votes

     Yes, it can. However, there can only be one public top-level class per .java file, and public top-level classes must have the same name as the source file.

     The purpose of including multiple classes in one source file is to bundle related support functionality (internal data structures, support classes, etc) together with the main public class. Note that it is always OK not to do this--the only effect is on the readability (or not) of your code.

     Other Answers

     Answered Jul 16, 2016 · 20 votes

     If you want to implement a public class, you must implement it in a file with the same name as that class. A single file can contain one public and optionally some private classes. This is useful if the classes are only used internally by the public class. Additionally the public class can also contain inner classes.

     Although it is fine to have one or more private classes in a single source file, I would say that is more readable to use inner and anonymous classes instead. For example one can use an anonymous class to define a Comparator class inside a public class:

     public static Comparator MyComparator = new Comparator() { public int compare(Object obj, Object anotherObj) {- } };

     The Comparator class will normally require a separate file in order to be public. This way it is bundled with the class that uses it.

     Other Answers

     Answered Dec 28, 2016 · 10 votes

     Yes, as many as you want!

     BUT, only one "public" class in every file.

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     3/5

   • Java: Why can a file not have more than one public class

     Top Answer

     Answered Jun 06, 2013 · 4 votes

     Because one .java file can contain only one public class.

     If you want these two classes to be public they have to be put into two .java files: A.java and B.java.

     From the JLS 7.6. Top Level Type Declarations:

     This restriction implies that there must be at most one such type per compilation unit. This restriction makes it easy for a Java compiler to find a named class within a package. In practice, many programmers choose to put each class or interface type in its own compilation unit, whether or not it is public or is referred to by code in other compilation units.

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     4/5

   • can i define more than one public class in a java package

     Top Answer

     Answered Nov 06, 2020 · 5 votes

     There can be more than one public class in package, but each public class needs to be declared in its own .java file. If you want these public classes that are in different .java files to be contained in the same package, simply put package mypack; at the very beginning of these .java files. This is the example, how you should name these files:

     package mypack; public class Box {...}

     package mypack; public class Circle {...}

     • Box.java : package mypack; public class Box {...}
     • Circle.java : package mypack; public class Circle {...}

     Note that files should be named with name of public class contained in it (if public class is present inside).

     By the way, be aware of naming conventions in Java language - it might save your and others time when looking at code - class names should start with capital letter, so in your case it should be Circle

     class and Circle.java

     , not circle

     class and circle.java

     .

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     5/5

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2. stackoverflow.com › questions › 21263607java - Can a normal Class implement multiple interfaces ...

   stackoverflow.com › questions › 21263607

   • Cached

   Yes, it is possible. This is the catch: java does not support multiple inheritance, i.e. class cannot extend more than one class. However class can implement multiple interfaces.

3. stackoverflow.com › questions › 20534726java - Do subclasses inherit interfaces? - Stack Overflow

   stackoverflow.com › questions › 20534726

   • Cached

   Dec 12, 2013 · The interface has to be entirely implemented throughout the hierarchy of sub classes and base class and has to be defined at the level where the interface implementation signature is located (implements Interface).

4. www.geeksforgeeks.org › java-and-multiple-inheritanceJava and Multiple Inheritance - GeeksforGeeks

   www.geeksforgeeks.org › java-and-multiple-inheritance

   • Cached

   Nov 16, 2022 · Multiple Inheritance is a feature of an object-oriented concept, where a class can inherit properties of more than one parent class. The problem occurs when methods with the same signature exist in both the superclasses and subclass.

5. stackoverflow.com › questions › 12162688Inheriting from multiple classes in Java (and possibly not ...

   stackoverflow.com › questions › 12162688

   • Cached

   Aug 28, 2012 · A class in Java can inherit from exactly one class (if you do not specify the base class, it's java.lang.Object ). The only way to inherit from three classes is if they inherit from each other in a chain: class A {} class B extends A {} class C extends B {}

6. www.geeksforgeeks.org › interfaces-and-inheritanceInterfaces and Inheritance in Java - GeeksforGeeks

   www.geeksforgeeks.org › interfaces-and-inheritance

   • Cached

   Sep 11, 2023 · Multiple Inheritance is a feature of an object-oriented concept, where a class can inherit properties of more than one parent class. The problem occurs when methods with the same signature exist in both the superclasses and subclass.

7. www.geeksforgeeks.org › how-to-implement-multipleHow to Implement Multiple Inheritance by Using Interfaces in ...

   www.geeksforgeeks.org › how-to-implement-multiple

   • Cached

   Apr 8, 2023 · Multiple Inheritance is a feature of an object-oriented concept, where a class can inherit properties of more than one parent class. The problem occurs when methods with the same signature exist in both the superclasses and subclass.

8. www.baeldung.com › java-inheritanceGuide to Inheritance in Java | Baeldung

   www.baeldung.com › java-inheritance

   • Cached

   Mar 17, 2024 · Simply put, in Java, a class can inherit another class and multiple interfaces, while an interface can inherit other interfaces. In this article, we’ll start with the need for inheritance, moving to how inheritance works with classes and interfaces.