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Java Programming Exercises, Practice, Solution

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Java is the foundation for virtually every type of networked application and is the global standard for developing and delivering embedded and mobile applications, games, Web-based content, and enterprise software. With more than 9 million developers worldwide, Java enables you to efficiently develop, deploy and use exciting applications and services.

The best way we learn anything is by practice and exercise questions. Here you have the opportunity to practice the Java programming language concepts by solving the exercises starting from basic to more complex exercises. A sample solution is provided for each exercise. It is recommended to do these exercises by yourself first before checking the solution.

Hope, these exercises help you to improve your Java programming coding skills. Currently, following sections are available, we are working hard to add more exercises .... Happy Coding!

List of Java Exercises:

• Basic Exercises Part-I [ 150 Exercises with Solution ]
• Basic Exercises Part-II [ 99 Exercises with Solution ]
• Methods [ 23 Exercises with Solution ]
• Data Types Exercises [ 15 Exercises with Solution ]
• Java Enum Types Exercises [ 5 Exercises with Solution ]
• Conditional Statement Exercises [ 32 Exercises with Solution ]
• Java recursive method Exercises [ 15 Exercises with Solution ]
• Math [ 27 Exercises with Solution ]
• Numbers [ 28 Exercises with Solution ]
• Java Constructor Exercises [ 10 exercises with solution ]
• Java Static Members Exercises [ 8 exercises with solution ]
• Java Nested Classes Exercises [ 10 exercises with solution ]
• Java Inheritance Exercises [ 9 exercises with solution ]
• Java Abstract Classes Exercises [ 12 exercises with solution ]
• Java Interface Exercises [ 11 exercises with solution ]
• Java Encapsulation Exercises [ 14 exercises with solution ]
• Java Polymorphism Exercises [ 12 exercises with solution ]
• Object-Oriented Programming [ 30 Exercises with Solution ]
• Exercises on handling and managing exceptions in Java [ 7 Exercises with Solution ]
• Java Lambda expression Exercises [ 25 exercises with solution ]
• Streams [ 8 Exercises with Solution ]
• Java Thread Exercises [ 7 exercises with solution ]
• Java Miltithreading Exercises [ 10 exercises with solution ]
• Array [ 77 Exercises with Solution ]
• Stack [ 29 Exercises with Solution ]
• Collection [ 126 Exercises with Solution ]
• String [ 107 Exercises with Solution ]
• Input-Output-File-System [ 18 Exercises with Solution ]
• Date Time [ 44 Exercises with Solution ]
• Java Generic Methods [ 7 exercises with solution ]
• Java Unit Test [ 10 Exercises with Solution ]
• Search [ 7 Exercises with Solution ]
• Sorting [ 19 Exercises with Solution ]
• Regular Expression [ 30 Exercises with Solution ]
• JavaFX [ 70 Exercises with Solution ]

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Methods in Java – Explained with Code Examples

Methods are essential for organizing Java projects, encouraging code reuse, and improving overall code structure.

In this article, we will look at what Java methods are and how they work, including their syntax, types, and examples.

Here's what we'll cover:

What are java methods.

• Types of Access Specifiers in Java – Public ( public ) – Private ( private ) – Protected ( protected ) – Default ( Package-Private )
• Types of Methods – Pre-defined vs. User-defined – Based on functionality

In Java, a method is a set of statements that perform a certain action and are declared within a class.

Here's the fundamental syntax for a Java method:

Let's break down the components:

• accessSpecifier : defines the visibility or accessibility of classes, methods, and fields within a program.
• returnType : the data type of the value that the method returns. If the method does not return any value, the void keyword is used.
• methodName : the name of the method, following Java naming conventions.
• parameter : input value that the method accepts. These are optional, and a method can have zero or more parameters. Each parameter is declared with its data type and a name.
• method body : the set of statements enclosed in curly braces {} that define the task the method performs.
• return statement : if the method has a return type other than void , it must include a return statement followed by the value to be returned.

Here's an example of a simple Java method:

In this example, the addNumbers method takes two integers as parameters ( a and b ), calculates their sum, and returns the result. The main method then calls this method and prints the result.

Compile the Java code using the terminal, using the javac command:

Methods facilitate code reusability by encapsulating functionality in a single block. You can call that block from different parts of your program, avoiding code duplication and promoting maintainability.

Types of Access Specifiers in Java

Access specifiers control the visibility and accessibility of class members (fields, methods, and nested classes).

There are typically four main types of access specifiers: public, private, protected, and default. They dictate where and how these members can be accessed, promoting encapsulation and modularity.

Public ( public )

This grants access to the member from anywhere in your program, regardless of package or class. It's suitable for widely used components like utility functions or constants.

In this example:

• The MyClass class is declared with the public modifier, making it accessible from any other class.
• The publicField is a public field that can be accessed from outside the class.
• The publicMethod() is a public method that can be called from outside the class.
• The main method is the entry point of the program, where an object of MyClass is created, and the public field and method are accessed.

Private ( private )

This confines access to the member within the class where it's declared. It protects sensitive data and enforces encapsulation.

• The MyClass class has a privateField and a privateMethod , both marked with the private modifier.
• The accessPrivateMembers() method is a public method that can be called from outside the class. It provides access to the private field and calls the private method.

Protected ( protected )

The protected access specifier is used to make members (fields and methods) accessible within the same package or by subclasses, regardless of the package. They are not accessible from unrelated classes. It facilitates inheritance while controlling access to specific members in subclasses.

• The Animal class has a protected field ( species ) and a protected method ( makeSound ).
• The Dog class is a subclass of Animal , and it can access the protected members from the superclass.
• The displayInfo() method in the Dog class accesses the protected field and calls the protected method.

With the protected access specifier, members are accessible within the same package and by subclasses, promoting a certain level of visibility and inheritance while still maintaining encapsulation.

Default ( Package-Private )

If no access specifier is used, the default access level is package-private . Members with default access are accessible within the same package, but not outside it. It's often used for utility classes or helper methods within a specific module.

• The Animal class does not have any access modifier specified, making it default (package-private). It has a package-private field species and a package-private method makeSound .
• The Dog class is in the same package as Animal , so it can access the default (package-private) members of the Animal class.
• The Main class runs the program by creating an object of Dog and calling its displayInfo method.

When you run this program, it should output the species and the sound of the animal.

How to Choose the Right Access Specifier

• Public: Use for widely used components, interfaces, and base classes.
• Private: Use for internal implementation details and sensitive data protection.
• Default: Use for helper methods or components specific to a package.
• Protected: Use for shared functionality among subclasses, while restricting access from outside the inheritance hierarchy.

Types of Methods

In Java, methods can be categorized in two main ways:

1. Predefined vs. User-defined:

Predefined methods: These methods are already defined in the Java Class Library and can be used directly without any declaration.

Examples include System.out.println() for printing to the console and Math.max() for finding the maximum of two numbers.

User-defined methods: These are methods that you write yourself to perform specific tasks within your program. They are defined within classes and are typically used to encapsulate functionality and improve code reusability.

• add is a user-defined method because it's created by the user (programmer).
• The method takes two parameters ( num1 and num2 ) and returns their sum.
• The main method calls the add method with specific values, demonstrating the customized functionality provided by the user.

2. Based on functionality:

Within user-defined methods, there are several other classifications based on their characteristics:

Instance Methods:

Associated with an instance of a class. They can access instance variables and are called on an object of the class.

Here are some key characteristics of instance methods:

Access to Instance Variables:

• Instance methods have access to instance variables (also known as fields or properties) of the class.
• They can manipulate the state of the object they belong to.

Use of this Keyword:

• Inside an instance method, the this keyword refers to the current instance of the class. It's often used to differentiate between instance variables and parameters with the same name.

Non-static Context:

• Instance methods are called in the context of an object. They can't be called without creating an instance of the class.

Declaration and Invocation:

• Instance methods are declared without the static keyword.
• They are invoked on an instance of the class using the dot ( . ) notation.

Here's a simple example in Java to illustrate instance methods:

• bark and ageOneYear are instance methods of the Dog class.
• They are invoked on instances of the Dog class ( myDog and anotherDog ).
• These methods can access and manipulate the instance variables ( name and age ) of the respective objects.

Instance methods are powerful because they allow you to encapsulate behavior related to an object's state and provide a way to interact with and modify that state.

Static Methods:

A static method belongs to the class rather than an instance of the class. This means you can call a static method without creating an instance (object) of the class. It's declared using the static keyword.

Static methods are commonly used for utility functions that don't depend on the state of an object. For example, methods for mathematical calculations, string manipulations, and so on.

Abstract Methods:

These methods are declared but not implemented in a class. They are meant to be overridden by subclasses, providing a blueprint for specific functionality that must be implemented in each subclass.

Abstract methods are useful when you want to define a template in a base class or interface, leaving the specific implementation to the subclasses. Abstract methods define a contract that the subclasses must follow.

Other method types: Additionally, there are less common types like constructors used for object initialization, accessor methods (getters) for retrieving object data, and mutator methods (setters) for modifying object data.

In this article, we will look at Java methods, including their syntax, types, and recommended practices.

Happy Coding!

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Defining Methods

Here is an example of a typical method declaration:

The only required elements of a method declaration are the method's return type, name, a pair of parentheses, () , and a body between braces, {} .

More generally, method declarations have six components, in order:

• Modifiers—such as public , private , and others you will learn about later.
• The return type—the data type of the value returned by the method, or void if the method does not return a value.
• The method name—the rules for field names apply to method names as well, but the convention is a little different.
• The parameter list in parenthesis—a comma-delimited list of input parameters, preceded by their data types, enclosed by parentheses, () . If there are no parameters, you must use empty parentheses.
• An exception list—to be discussed later.
• The method body, enclosed between braces—the method's code, including the declaration of local variables, goes here.

Modifiers, return types, and parameters will be discussed later in this lesson. Exceptions are discussed in a later lesson.

The signature of the method declared above is:

Naming a Method

Although a method name can be any legal identifier, code conventions restrict method names. By convention, method names should be a verb in lowercase or a multi-word name that begins with a verb in lowercase, followed by adjectives, nouns, etc. In multi-word names, the first letter of each of the second and following words should be capitalized. Here are some examples:

Typically, a method has a unique name within its class. However, a method might have the same name as other methods due to method overloading .

Overloading Methods

The Java programming language supports overloading methods, and Java can distinguish between methods with different method signatures . This means that methods within a class can have the same name if they have different parameter lists (there are some qualifications to this that will be discussed in the lesson titled "Interfaces and Inheritance").

Suppose that you have a class that can use calligraphy to draw various types of data (strings, integers, and so on) and that contains a method for drawing each data type. It is cumbersome to use a new name for each method—for example, drawString , drawInteger , drawFloat , and so on. In the Java programming language, you can use the same name for all the drawing methods but pass a different argument list to each method. Thus, the data drawing class might declare four methods named draw , each of which has a different parameter list.

Overloaded methods are differentiated by the number and the type of the arguments passed into the method. In the code sample, draw(String s) and draw(int i) are distinct and unique methods because they require different argument types.

You cannot declare more than one method with the same name and the same number and type of arguments, because the compiler cannot tell them apart.

The compiler does not consider return type when differentiating methods, so you cannot declare two methods with the same signature even if they have a different return type.

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Developed by Sun Microsystems in 1995, Java is a highly popular, object-oriented programming language. This platform independent programming language is utilized for Android development, web development, artificial intelligence, cloud applications, and much more.

In this tutorial, we will cover everything from the basics of Java syntax to advanced topics like object-oriented programming and exception handling. So, by the end of this tutorial, you will have a strong understanding of Java and be ready to start writing your own Java applications. So let’s get started on this comprehensive Free Java programming course !

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Overview of Java

Basics of java, input/output in java, flow control in java, operators in java, arrays in java, strings in java, oops in java, classes of java, interfaces in java, methods in java, packages in java, collection framework in java, collection classes in java, memory allocation in java, exception handling in java, multithreading in java, synchronization in java, file handling in java, java networking, java se 8 features, java date & time, java miscellaneous, interview questions on java, java practice problems, java jobs & opportunity, get started with free java tutorial.

Here in this section, you will find all the free resources that you need to become zero to mastery in the process of learning Java programming language .

• Introduction to Java
• History of Java
• Java vs C++ vs Python
• How to Download and Install Java?
• Setting Up the Environment in Java
• How to Download and Install Eclipse on Windows?
• Java Development Kit (JDK) in Java
• JVM and its architecture
• JDK Vs JRE Vs JVM
• Just In Time Compiler
• Byte Code Vs Machine Code
• Java Basic Syntax
• First Java Program (Hello World)
• Datatypes in Java
• Primitive Vs Non-Primitive Datatypes
• Java Identifiers
• Java Variables
• Java Keywords
• Scope of Variables
• Wrapper Classes in Java
• How to take Input from users in Java
• Scanner class in Java
• BufferedReader class in Java
• Scanner vs BufferedReader in Java
• Ways to Read Input from Console in Java
• Print Output in Java
• print() Vs println() in Java
• Formatted Outputs in Java
• Decision making in Java
• If Statement in Java
• If-Else Statement in java
• If-Else-If ladder in Java
• Loops in Java
• Do while loop
• For each loop
• Continue Statement in java
• Break Statement In Java
• Usage of Break in Java
• Return Statement in Java
• Arithmetic Operator
• Unary Operator
• Assignment Operator
• Relational Operator
• Logical Operator
• Ternary Operator
• Bitwise Operator
• Introduction to Arrays in Java
• Arrays class in Java
• Multi-Dimensional Array in Java
• How to declare and initialize 2D arrays in Java
• Jagged array in Java
• Final Arrays in Java
• Reflect Arrays in Java
• Java util.Arrays Vs reflect.Arrays
• Java Array Programs
• Introduction of Strings in Java
• String class in Java Set-1 | Set-2
• Why strings are immutable in Java?
• StringBuffer class in Java
• StringBuilder class in Java
• Strings vs StringBuffer vs StringBuilder in Java
• StringTokenizer class in Java Set-1 | Set-2
• StringJoiner in Java
• Java String Programs

OOPS in Java refers to Object-Oriented Programming concepts implemented in the Java programming language. Java’s OOP features include classes, objects, inheritance, polymorphism, and encapsulation, enabling modular and efficient code development. Understanding OOPS in Java is essential for building robust, scalable, and maintainable software applications.

• OOPS Concept in Java
• Why Java is not a purely Object-Oriented Language?
• Classes and Objects
• Naming Convention in Java
• Access Modifiers in Java
• Constructors in Java
• Four pillars of OOPS in Java
• Inheritance in Java
• Abstraction in Java
• Encapsulation in Java
• Polymorphism in Java
• This reference in Java

Classes in Java are the blueprint for creating objects and defining their properties and behaviors. They are the fundamental building blocks of Java programs, enabling the creation of reusable and modular code. Classes can contain fields, methods, constructors, and nested classes, providing a wide range of functionality and flexibility.

• Understanding classes and objects in Java
• Class vs interface
• Singleton class in java
• Object class in java
• Inner class in java
• Abstract classes in java
• Throwable class in java

Interfaces in Java are abstract types that define a set of methods that a class must implement. They provide a way to achieve abstraction, multiple inheritance, and loose coupling in Java programs. Interfaces are useful for defining common behaviors and functionalities that can be shared across different classes, leading to more modular and reusable code. Mastering interfaces in Java is crucial for building flexible and extensible software applications.

• Java Interfaces
• Interfaces and Inheritance in Java
• Class Vs Interface in Java
• Functional Interface
• Nested Interface
• Marker Interface
• Comparator Interface
• Introduction to methods in Java
• Different method calls in Java
• Static methods Vs Instance methods in Java
• Abstract methods in Java
• Method Overriding in Java
• Method Overloading in Java
• Method Overloading Vs Method Overriding
• Java Packages
• How to create a package in Java
• java.util package
• java.lang package
• java.io package
• Java Collection Framework
• Collections class in Java
• Collection Interface in Java
• List Interface in Java
• Queue Interface in Java
• Map Interface in Java
• Set Interface in Java
• SortedSet Interface in Java
• Deque Interface in Java
• Comparator in Java
• Comparator Vs Comparable in Java
• Iterator in Java
• ArrayList in Java
• Vector class in Java
• Stack class in Java
• LinkedList in Java
• Priority Queue in Java
• HashMap in Java
• LinkedHashMap in Java
• Dictionary in Java
• HashTable in Java
• HashSet in Java
• TreeSet in Java
• LinkedHashSet in Java
• Java Memory Management
• How are Java objects stored in memory
• Stack vs Heap memory allocation
• Types of memory areas allocated by JVM
• Garbage Collection in Java
• Heap and Stack memory allocation
• Types of JVM Garbage Collectors in Java
• Memory leaks in Java
• Java Virtual Machine(JVM) Stack Area
• Exceptions in java
• Types of Exceptions
• Checked Vs Unchecked Exceptions
• Try, Catch, Finally, throw, and throws
• Flow control in Try catch block
• Throw vs Throws
• Final vs Finally vs Finalize
• User-defined custom exception
• Chained Exceptions
• Null pointer Exceptions
• Exception handling with method Overriding
• Introduction to Multithreading in Java
• Lifecycle and Stages of a Thread
• Thread Priority in Java
• Main Thread in Java
• Thread class
• Runnable interface
• How to name a thread
• start() method in thread
• run() vs start() Method in Java
• sleep() method
• Daemon thread
• Thread Pool in Java
• Thread Group in Java
• Thread Safety in Java
• ShutdownHook
• Multithreading Tutorial
• Java Synchronization
• Importance of Thread synchronization in Java
• Method and Block Synchronization in Java
• Local frameworks vs thread synchronization
• Atomic Vs Volatile in Java
• Atomic Vs Synchronized in Java
• Deadlock in Multithreading
• Deadlock Prevention and Avoidance
• Lock Vs Monitor in Concurrency
• Reentrant Lock
• File Class in java
• How to create files in java
• How to read files in java
• How to write on files in java
• How to delete a file in java
• File Permissions
• File Writer
• FileDescriptor class
• RandomAccessFile class
• Introduction to Java Regex
• How to write Regex expressions
• Matcher class
• Pattern class
• Quantifiers
• Character class
• Introduction to Java IO
• Reader Class
• Writer Class
• FileInput stream
• File Output stream
• BufferedReader Input Stream
• BufferedReader Output stream
• BufferedReader vs Scanner
• Fast I/O in Java
• Introduction to Java Networking
• TCP architecture
• UDP architecture
• IPV4 Vs IPV6
• Connection-oriented Vs connectionless protocols
• Socket programming in Java
• Server Socket class
• URL class and methods
• Lambda Expressions
• Streams API
• New Date/Time API
• Default Methods
• Functional Interfaces
• Method references
• Optional class
• Stream Filter
• Type Annotations
• String Joiner
• Date Class in Java
• Methods of the Date class
• Java Current Date and time
• Compare dates in Java
• Introduction to Java JDBC
• JDBC Driver
• JDBC Connection
• Types of Statements in JDBC
• JDBC Tutorial
• Introduction to Reflection API
• Java IO Tutorial
• JavaFX Tutorial
• How to Run Java RMI application?
• Java 17 New Features
• Core Java Interview Questions
• Java Multiple Choice Questions

Features of Java

• Java has been one of the most popular programming languages for many years.
• Java is Object Oriented. However, it is not considered as pure object-oriented as it provides support for primitive data types (like int, char, etc)
• The Java codes are first compiled into byte code (machine-independent code). Then the byte code runs on Java Virtual Machine (JVM) regardless of the underlying architecture.
• Java syntax is similar to C/C++. But Java does not provide low-level programming functionalities like pointers. Also, Java codes are always written in the form of classes and objects.
• Java is used in all kinds of applications like Mobile Applications (Android is Java-based), desktop applications, web applications, client-server applications, enterprise applications, and many more.
• When compared with C++, Java codes are generally more maintainable because Java does not allow many things which may lead to bad/inefficient programming if used incorrectly. For example, non-primitives are always references in Java. So we cannot pass large objects (like we can do in C++) to functions, we always pass references in Java. One more example, since there are no pointers, bad memory access is also not possible.
• When compared with Python, Java kind of fits between C++ and Python. The programs are written in Java typically run faster than corresponding Python programs and slower than C++. Like C++, Java does static type checking, but Python does not.

Applications of Java

Here in this section, we have added some of the applications that were developed using the Java programming language.

• Mobile Applications
• Desktop GUI Applications
• Artificial intelligence
• Scientific Applications
• Cloud Applications
• Embedded Systems
• Gaming Applications

Keep up your pace and try hard till you excel in it. This will need some motivation and resources to Practice Java. So, there are few resources mentioned below this will help you in your journey:

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Java Latest & Upcoming Features

Java SE 21 Released: September 2023 Java SE 21 is the latest stable release, featuring:

• Hidden Classes (Preview): Introduces a mechanism to restrict access to specific members of a class, enhancing modularity and code maintainability.
• Improved Garbage Collector Ergonomics (JEP 429): Simplifies configuration and monitoring of the garbage collection process.
• API Updates : Enhancements to existing APIs, including java.io.file for better file handling capabilities.

Java SE 22 Released: March 19, 2024 Java SE 22 introduces:

• Foreign Function & Memory API (JEP 454): Enhances interoperability with native code.
• Unnamed Variables & Patterns (JEP 456): Adds support for unnamed variables and patterns.
• Structured Concurrency (JEP 462, Second Preview): Simplifies multithreaded programming by structuring concurrency.
• String Templates (JEP 459, Second Preview): Provides a new syntax for creating and manipulating strings.
• Vector API (JEP 460, Seventh Incubator): Offers a portable and low-level abstraction for SIMD programming.

Upcoming Features (Expected in Java SE 23 – September 2024)

• Vector API (Incubator): A new API designed for high-performance vector computations, potentially beneficial for scientific computing and machine learning applications.
• Project Panama (Preview): Aims to improve interoperability between Java and native code, simplifying interactions with non-Java libraries and frameworks.

Trends in Java Development:

• Java continues to prioritize features that enhance application performance and developer experience.
• Java’s strong position in cloud environments is expected to hold as cloud computing remains a dominant trend.
• Java’s suitability for building scalable and modular systems aligns well with the popularity of microservices architectures.
• Expect to see Java evolving to integrate more seamlessly with technologies like artificial intelligence, big data, and the Internet of Things (IoT).

Java Programming Tutorial: FAQs

Why use java .

Java is simple to understand programming language because doesn’t contain concepts like : Pointers and operator overloading and it is secure and portable.

What are the major concepts in Java?

There are 4 major concept in Java that is abstraction, encapsulation, polymorphism, and inheritance. Along with this Java also works with three OOPs concept

How Java different to C++ ?

Why Java is so popular programming language?

Java is based on object model hence it is one the popular programming language.

What are the scope of Java Technologies for Web Applications?

Java Technologies for Web Applications are a set of Java-based technologies that are used to develop web applications. These technologies include: Java Servlet API JavaServer Pages JavaServer Faces Enterprise JavaBeans JDBC (Java Database Connectivity) Java Messaging Service (JMS): JavaMail API: JAX-WS

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Method within a method (homework assignment)

I have a homework assignment where I am asked to:

Write a method sort(int[] arr) that takes an integer array and uses a method from a previous exercise to determine if the array is sorted in increasing order or not. If it is already sorted, it should return the array, if it is not, the method should sort the array before returning it.

My problem is that I don't know how I should approach this assignment? Should I modify the previous method, call it within a new method or can I create a method within the method? This is the previous method that I wrote:

Thanx in advance

• 8 You can't declare methods within methods. Your assignment is telling you to use a method from a previous exercise to check if the array is sorted in increasing order or not. Use it. –  proulxs Commented Sep 30, 2014 at 19:17
• public void bar() { foo(); } I call the foo() method from my bar() method. Same concept as your assignment. –  Compass Commented Sep 30, 2014 at 19:19

3 Answers 3

In the interest of you actually learning something, here's my solution:

Here is the documentation for Arrays.sort

Not only is this more concise, it also does the sort in-place. This means that instead of copying the array you pass in, doing the work, and then returning the copy, it just does the work on the original array. This makes it slightly faster and means it takes up a minimal amount of extra space. Not that big a deal when your input size is 10, but it is when you get to 10 million. Also, note the wording of the assignment: If it is already sorted, it should return the array, if it is not, the method should sort the array before returning it. Technically, returning a copy of the original array is not what the assignment wants. It wants the original.

So it's short, clean, fast, and memory efficient. It must be good, right?

No, because it has one huge flaw. It breaks the implied contract of the method. A function that changes its arguments should not return anything, and a function that returns something should not modify its arguments. This is a basic principle of software engineering (and one that Arrays.sort demonstrates). Violating this can cause huge problems for those who assume you're competent and won't break this rule.

If we follow the rule, sort should be this:

So tell your teacher an armored hamster you met on the Internet said to stop teaching you poor interface design.

• Thank you very much! This seems like a better approach. I will definitely tell him that haha. –  Morten Falk Commented Oct 1, 2014 at 7:14

I read "uses [the] method" to mean "calls the method". That said, testing for sortedness before sorting seems somewhat pointless, so it might be worth double-checking with whoever gave you that assignment.

One issue with your previous method is that it doesn't return anything. You'll need to do something about that to make it useful.

• 1 There are certain sorting algorithms that perform very poorly on sorted data, so doing a sanity check beforehand is reasonable. –  Floegipoky Commented Sep 30, 2014 at 19:25
• True. In the actual assignment I am invoking the method and printing the result. –  Morten Falk Commented Sep 30, 2014 at 19:26
• @Floegipoky: Point taken. And, again, it's only an exercise after all. –  NPE Commented Sep 30, 2014 at 19:28
• I think the point is just learning how to do it regardless of it being pointless. So what should I do in practice? I know how to use the java.util.Arrays.sort method but my problem is combining the method that I already wrote with a new method that returns the array or sorts it... –  Morten Falk Commented Sep 30, 2014 at 19:30

This is what you want to do:

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