“String is a combination of characters”: This is the common definition of a String that you will hear from every programmer. However, it is not confined to this, there is a lot more detailing to know about this concept. There’s a lot more to this definition and features of a string. Different concepts like the subsequence of a string, and substring are most commonly asked in technical interviews.
The string is one of the most special classes in Java and is different from other classes. Given that the concept of String is used everywhere, it is important to learn in-depth about it.
Here, we have come up with 10 things that you need to know about String as a Java programmer. So, let’s begin.
Things About Strings Every Java Programmer Should Know
Solving problems related to a subsequence of a string or a substring can be tricky sometimes. Strings do not work in the same way as other classes in Java.
These 10 things will give you a better glimpse of a String and make it easier for you to resolve problems related to it.
Do Not Store Sensitive Data
Strings can have security threats. Therefore, strings are not appropriate for storing sensitive information like SSN, critical information, and passwords. Since a String in Java is immutable, you can not delete data from it. The String data is stored in the Java heap far away. This property possesses risk as anyone who has access to the Java memory can access the string content.
Use Trim() To Remove Spaces
If your string has white spaces on the end, you can use the Trim() function. This function will remove the spaces from both ends of the string. In case it removes the space from the given string, a new string will be formed. Otherwise, it will return you the old string.
“+” Is Overloaded For Concatenation
Although operator overloading is not possible in String in Java, there is an exception. The “+” operator in a string is used to concatenate or combine two strings. This operator is also used to covert double, int, long, or Char to string by simply concatenating it with an empty string.
Strings Are Not Null Terminated
String in Java does not end with a null character. Unlike C++ or C, this does not happen in Java. Instead, a string in Java is treated as an object and is then backed by an array of characters. Also, you can call the array by using the toCharArray() function.
String Pool Manages Strings
Since we have mentioned that String is treated as an Object in Java, it is managed differently. Strings are managed in the string pool in Java. This is a special space in Java memory. So, every time we mention or create a new String object, JVM checks the string pool.
If it has the same String pool, it will return the same. However, if the string object is not present in the pool, it will create a new one. Other than this, if you have used the new operator, JVM will not check the string pool.
Strings Are Immutable In Java
Strings in Java are immutable. This means that you will not be able to modify the content of the string. In case you choose to modify it by using different methods like toUpperCase() or toLowerCase(), it will not make changes but create a new string. Moreover, the strings are final and therefore, none of its functionality can be changed or overridden.
Employ Equal Methods To Compare
You can also use Equal methods to compare the content of two strings. The String class overrides the equal method and results in content equality. Therefore, if you anytime wish to compare the objects of two strings, you can do it using the equals() function.
Employ LastIndex() Or indexOf() To Search
String in Java offers you in-built methods to check if a substring, object, or character is present in the given string or not. However, these methods can not be used to find the subsequence of a string.
You can use the IndexOf() function to find the location of a character or a substring in the string. In case, it is not available in the string, it will return -1 in the output. The LastIndexOf() function performs the same function but it scans from the end of the string.
Utilize Substring To Get Part The Part Of A String
The SubString() function in Java can be used to find different parts of the given string. To find a SubString, you need to begin and end at an index of an array and the SubString method will return a character from the given range. Also, you must know that the SubString is also backed by an array of characters which is then used by the original string.
Split() Function Can Be Used To Split A String
String in Java also works with regular expressions. It provides you with a Split(regex) function which can be used to split the string based on the regular expression entered. This feature of a string is mostly used when you are working with the CSV file. It can be used if you want to check and have different parts of a particular string. Moreover, there are various other methods available to split a string.
Conclusion
Understanding the features and concepts of a string is important to employ the concept properly. String in Java is completely a different concept than in other languages. Therefore, it is obvious to get confused.
However, if you are starting from scratch or you are going for an interview as a Java developer, String is the most important concept that you should emphasize.
Many larger firms like Amazon, Google, and Cognizant ask questions related to the subsequence of a string, substring, and other functionalities of a string. You may also be asked to write a code on such a subject.
Therefore, you are required to practice problems like sort array of 0 1 2, the reverse of an array, and more as much as you can before going for an interview.
Also Read – Why is Java the Best Language for a Web App Development Project?