An Introduction to the Java Substring Method

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Java is superb, each the drink and the programming language, that may be a level in actual fact. But I have to digress as a result of right this moment we’re solely speaking about the programming language. More particularly, we’ll talk about a string manipulation technique referred to as the substring technique.

In any programming language, interacting with and manipulating strings is an important job. Developers want to carry out this job usually, and consequently, the people who oversee the progress of a programming language have taken steps to make it simpler. For Java, an important instance of those efforts might be present in the substring technique.

This publish will go over what the substring technique does, the way it works, and how one can implement it into your work. Without any extra delay, let’s get this get together perking.

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Java String API

In Java, string strategies are additionally generally referred to as string name APIs, and the two phrases are thought of interchangeable. To perceive what this implies, let’s shortly take a look at how Java handles strings.

Strings in Java are thought of objects and are immutable which suggests they can’t be modified after creating them. New strings that get created are added to the Java fixed pool, that is the place all constants — immutable — objects are saved to be used as wanted.

When strings are referenced Java will examine for them in the fixed pool. If it’s current, it can return an occasion of it. The solely time a string will get added to the fixed pool is that if a reference to one isn’t current in the pool.

Java String Substring

The Java substring technique has two variations, the first requires a beginning index, and the second variant makes use of the beginning index and an ending index. Each model performs in another way, however each return a brand new string that may be a substring of the first.

This line of code calls on the public class String to entry the substring technique inside it. This is the place entry to string strategies comes from. Next, let’s take a look at some examples of the two variants of the substring technique.



Java String Substring Start Index Integer

The substring technique takes a single integer that identifies the beginning index, with this variant of the technique it can proceed to the finish of the string. You will want to begin by making a string earlier than you are able to do something with the substring technique.

Let’s assume the above string for the the rest of this publish, and use this to create a few substrings. With the first variant of the substring technique, you may create a substring of “awesome!” utilizing the following code.


The above code might look a bit complicated, so let’s break it down a bit additional. First, this line of code accesses the print operate from the System.out object. All this actually does is present the capability to print info to the console. Inside of the print technique we name the substring technique on the beforehand created string.


The substring technique then searches the goal string for a personality at index 11, it then extracts a substring primarily based on all the characters in the string past that index. This efficiently creates a substring of “awesome!” as anticipated.

This could be very highly effective, however what if you’d like to create a substring from the starting or center of a bigger string? Well, that will be the place the second substring variant comes into play.

Java String Substring Start and End Index Integer

The second variant of the Java substring technique takes two parameters, a begin index and an finish index. This is vital as a result of it permits us to dictate the place the substring ought to cease extracting characters for the new string. Now that we have now mentioned the way it works, let’s take a look at an instance of it.

/* utilizing substring() to extract substring*/
System.out.print(Str.substring(0, 7));

Final Takeaways on Using the Java String Substring Method

There isn’t far more to the Java String substring technique and we’ve lined the whole lot you want to know to get began Let’s recap the most vital factors to keep in mind about how the technique works.

  • The substring technique has two variant syntaxes
  • The first model solely accepts one parameter which is a begin index for the technique
  • The second model accepts two parameters: the begin and finish indexes for the technique.
  • The begin index for each variations is inclusive, which suggests it contains the character in that index location.
  • The finish index is non-inclusive and as such doesn’t embrace the character at that index location.

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