C# and Java are two very popular programming languages, each regularly topping the charts of the top 5 most widely use programming languages in the world. Both programming languages share a similar syntax and structure, and are often considered to be part of the same family of programming languages – notably, the “C-family”, which includes C, C++, and Java. Differences do exist between the two, however, and in programming tutorial, we will discuss the key differences between C# and Java, such as their syntax, performance, and memory management. Code examples will also be provided to better illustrate the differences in variable declaration, class creation, the use of pointers, string manipulation, and exception handling.
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Differences Between C# and Java
Below are some key differences developers will find when choosing between working with C# and Java for their software development, including:
- Language type
- Syntax
- String Manipulation
- Exception and Error handling
- Performance
- Memory management and resource allocation
Language Type
One of the most important differences between C# and Java has to do with the type of language they are or their paradigm. Java is largely considered an object-oriented language programming language, which means it focuses on structuring programs through the use of objects and classes. In reality, however, Java is not a true OOP language, but, rather, has features of object oriented programming, such as inheritance, polymorphism, the use of classes and objects, and encapsulation. The use of primitive data types versus data types that are strictly objects, disqualifies it from being 100% object oriented.
Meanwhile, C#, is built on several development paradigms, including object-oriented, functional, and imperative programming.
A brief note: object-oriented programming (OOP) is based on the concept of objects, which contain data and the code required to manipulate that data. In Java, objects are created using classes, which can be thought of as “blueprints” that help define the attributes and methods that an object can possess. C# uses classes as well in order to create objects, but it supports functional programming concepts like lambda expressions and anonymous methods as well.
Syntactical Differences
C# and Java have several important syntactical differences as well, which can significantly impact how the languages are used. One of the main differences in their syntax has to do with the way Java and C# handle variable declaration.
In Java, variables are declared using the following syntax:
= ;
Here is some sample code showing how to create and declare a variable in Java:
int x = 10; String name = "Nick";
Meanwhile, in C#, variables are declared using the following syntax:
= ;
Here is some sample code showing how to create and declare a variable in C# – can you spot the difference?
int x = 10; string name = "Nick";
You may have noticed that C# uses the keyword string instead of String, which is used by Java. A small, but notable difference.
Another difference between C# and Java with regards to data types is how pointers are handled. Java, for its part, does not have pointers, whereas C# does.
In C#, you can declare a pointer using the “*” symbol, as shown in the example code below:
int* pointer;
The above C# code declares a pointer with an integer (or int) variable. The pointer can be assigned a memory address, which marks it for later use when a programmer needs to manipulate or reference the value stored in that specific memory address.
Class Differences in C# and Java
Both C# and Java rely on classes are to define objects. However, the way each declares a class differs. In Java, classes are declared with the class keyword, as shown in the following code example:
public class ComicBook {
private String title;
private int issue;
public ComicBook(String title, int issue) {
this.title = title;
this.issue = issue;
}
public String getTitle() {
return title;
}
public int getIssue() {
return issue;
}
}
The code above defines a ComicBook class with two private fields: title and issue. The class additionally includes a constructor that takes two parameters – title and issue and two methods: getTitle() and getIssue().
In C#, classes are also declared using the class keyword, as shown here:
public class ComicBook {
private string title;
private int issue;
public ComicBook(string title, int issue) {
this.title = title;
this.issue = issue;
}
public string GetTitle() {
return title;
}
public int GetIssue() {
return issue;
}
}
You may have noticed that the syntax for declaring classes is almost identical between C# and Java. However, C# uses lowercase for method names while Java makes use of camel case.
Another difference involves how access modifiers are used. In Java, access modifiers such as public, private, and protected control the visibility of a class, method, or field, as well as define how they can be accessed. In C#, access modifiers are also used, but they are preceded by the accessibility keyword. Observe the code below:
public class ComicBook {
private string title;
private int issue;
public ComicBook(string title, int issue) {
this.title = title;
this.issue = issue;
}
internal string GetTitle() {
return title;
}
internal int GetIssue() {
return issue;
}
}
Here, the internal keyword is used versus public</b, making the methods visible only within the same assembly.
You can learn more about C# access modifiers in our tutorial: C# Access Modifiers.
String Manipulation in Java and C#
Manipulating strings is a common task in all programming languages, and C# and Java are no exceptions. Both languages provide similar functionality when it comes to working with strings, but each uses different syntax to achieve the same results. For instance, In Java, strings are objects that can be created using the String class. Here is some example code showing how to create a string in Java using the String class:
String name = "Nick"; int length = name.length();
In this Java code, the length() method gets the length of the string. In C#, strings are also objects, but they get created using the string keyword instead, as shown in this code snippet:
string name = "Nick"; int length = name.Length;
Notice, too, that the length() method is replaced with the Length property in C#.
Exception Handling Differences in C# and Java
Both C# and Java have mechanisms and features to help developers handle exceptions. Java, for its part, uses try-catch blocks for exception handling. Here is an example of how to handle exception with try-catch blocks in Java:
try {
// code that yields an exception error
} catch (Exception e) {
// code to retrieve and process the exception
}
Meanwhile, in C#, exceptions, too, are handled using the try-catch block method, as shown here:
try {
// code that yields an exception error
} catch (Exception e) {
// code to retrieve and process the exception
}
Application Performance
Application performance is also important when choosing a programming language. C# and Java are both compiled languages, meaning their code is converted into machine code prior to execution. That being said, there are differences in how each language is optimized, which, in turn, impacts performance.
Typically, developers consider C# to be faster than Java. This is especially true when it comes to memory management. C# makes use of a garbage collector to manage memory, which makes memory management more efficient. Java uses its own form of garbage collection via the Java Virtual Machine (JVM) and Just-in-Time compilation (JIT) which optimizes code for use on specific platforms.
You can learn more about JIT and the JVM in our tutorial: What is the Java Virtual Machine?
Memory Management
As discussed above, memory management is another important factor when deciding between C# and Java, who both rely on garbage collectors to manage memory. This reliance makes it so developers do not need to worry about manually allocating and deallocating memory resources. There are differences to note, mind you, in how C# and Java garbage collectors work, which can impact memory usage.
As stated, C# is generally considered more efficient in terms of memory management compared to Java. This is because C# uses a generational garbage collector, meaning objects that have been recently created are more likely to be collected than objects that have not. This leads to more efficient use of memory resources when compared to Java, which uses a mark-and-sweep approach to garbage collection when clearing temporary data that is no longer required.
Which is Better: C# or Java?
When choosing between C# and Java, your decision will ultimately depend on the needs and requirements of the software project and the personal preferences of the developer. C# is a great choice for Windows-based applications and if you want to code in the ,NET framework, especially if your application will require high performance and efficient memory management. Java, for its part, is a great choice for cross-platform development applications that can run regardless of system architecture or hardware and is great for web-based applications.
Final Thoughts on C# versus Java
In this programming tutorial, we look at two popular programming language options: C# and Java. We learned that both languages are object-oriented (or have object oriented features) and share similar syntax. There are differences in their paradigms, syntax, performance, and memory management, however, which sets them apart. C# and Java both have their strengths and weaknesses, and choosing the right one is largely based on project needs. Understanding their differences can help developers and programmers choose the right language for their software development projects and help optimize their development process.
