Most of the IDEs warn us about the errors before we run our code. The compiler will sometimes not point to the root cause of the error, so we should fix the code in the preceding lines. So it is important to look for the root cause of the error. Sometimes this error can also cause multiple other errors in our code. Usually, it is pretty easy to resolve this error. In this tutorial, we learned the reasons behind the illegal start of expression error. This will make the compiler throw the illegal start of expression error. For example, in the code below, we didn't enclose the asterisk(*) in quotes. Then an illegal start of expression error occurs If we forget the quotes and the string doesn't contain a valid variable name. So quotes are important to recognize them as strings and not as special characters. Strings or characters can also contain special characters or operators. Strings and char types must be enclosed in quotes. This will result in the illegal start of expression error. For example, in the code below, the print() method has an inner class(ClassThatPrints) inside it with a public modifier. Methods cannot contain any access modifier. But note that this inner class should not begin with any access modifiers. These classes are called Method-Local Inner Classes, and their scope is restricted to just the method. Java allows us to write a new class inside a method, but the class will be local to the method. This will result in an illegal start of expression error. Unlike some other programming languages like Python, Java does not support nested methods or methods inside a method. Removing the protected access modifier will fix the above code. Protected String str = 'protected access modifier' The following code won't compile because we have used the protected access modifier inside the print() method. If this rule is violated, then the compiler returns an illegal start of expression error. We cannot use access modifiers-like private, protected, or public-with local variables. Variables inside any method or block are called local variables, and their scope is limited to that block. To fix the error, add the curly brace at the correct location. When we try to compile the above code using javac, we will get the following result. The following code shows a simple example of this scenario. A missing curly brace will violate the syntax of Java programming, and the code won't compile. The illegal start of expression error can occur if we omit an opening or closing curly brace. In this tutorial, we will learn the reasons behind this error and how to resolve it. We can easily fix it if we know the cause of the error. It is a dynamic error and occurs during compile-time when we use the javac command.

The illegal start of expression is a common error encountered when working with Java.

Illegal start of expression