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Cannot find symbol error when importing enum class

So I'm facing a cannot find symbol error when static importing an enum in a class that depends on it. They are both in separate files within the same directory. I've omitted an explicit package name.
TokenType.java
// No imports
enum TokenType {
ADD, MINUS, MULTIPLY, DIVIDE,
...
}
Scanner.java
import java.util.ArrayList;
import java.util.List;
import java.util.HashMap;
import java.util.Map;
import static TokenType.*; // <--- (error: cannot find symbol)
class Scanner {
private static final Map <String, TokenType> keywords; // <--- (no error; javac can resolve the class name just fine)
static {
keywords = new HashMap<>();
keywords.put("+", ADD); // <-- (error: cannot find symbol, which makes sense)
keywords.put("-", MINUS);
...
}
...
}
I'm just not sure how to proceed. The names are all typed correctly, and there is only one TokenType class so there isn't a class conflict. My other classes in the project directory have no nested classes, do not extend/implement from other classes, or import libraries that have a TokenType class in their dependencies. I've cleaned my directory of all stale classes before each compile, and even changed the order in which I'm calling javac. Any help would be wonderful, thank you.
EDIT: Solution was to put them in a named package. Java doesn't allow imports from default package.

From the fact that the compiler can resolve the simple name TokenType in Map <String, TokenType>, it seems like TokenType is declared in the same package as Scanner.
You also said that you "omitted an explicit package name", which implies that both of these classes are not declared in the default package (static imports are not possible if they are in the default package), but some package with a name. Let's suppose that both of them are in
package com.example.foo;
Then you need to do:
import static com.example.foo.TokenType.*;
Note that even if you are in a location where the type is accessible with its simple name, you still need to use its canonical name (basically with the package name fully written out) in a static import declaration., and the name has to be qualified (in the form of X.Y), which is why classes in the default package don't work.

Import a class with same name as current class

Let's say I have this Java class:
package com.version1;
class Sample
{ ... }
And in another Sample class, I want to import the Sample class from com.version1 package:
package com.version2; // Now it's a different package
import com.version1.Sample; // From another package
public class Sample
{...}
Please note: I need to import a class with same name as the current class, not 2 classes with same name.
So the question: Importing two classes with same name. How to handle? is not similar.

You simply can't have two classes referenced by the same short name. So the solution is actually the same one as in the case of importing two classes with the same name:
You'll have to reference the other class by its fully qualified class name and your local one by its short name. You could even use the FQCN for both, if that helps readability in your case.

Import a single class in Java

Simple question but even though googled it a lot I could not find the answer.
Is it possible to import a class outside a package?
Let's say I have 2 folders A and B with a .java file in each, is it possible by using the clause import to import the class contained in A? import A.Aclass ? or it's mandatory using package syntax whenever there is the keyword import?

Yes it is possible to import the class with the import statement. For better understanding let's assume that you have three folders foldera, folderb and folderc where foldera contains a .java file named "ClassA.java", folderb contains another .java file named "ClassB.java" and folderc contains a .java file named "ClassC.java". Now, if you want to uses the member data and operations of "ClassA.java" in "ClassC.java" you can use the import statement as shown below:
import foldera.ClassA
If you want to use the member data & operations of "ClassB.java" in "ClassC.java" it is also possible with the import statement
import folderb.ClassB
As per the java source file declaration rule, if the class is a part of a package, the package statement must be the first line in the source code file, before any import statements that may be present. In this example, the first line of "ClassC.java" source file must be package folderc since it is located in folderc. Similarly, the first line of "ClassA.java" source file must be package foldera, and the first line of "ClassB.java" source file must be package folderb.
Hope now you are clear with the concept!
Thank you...

Well, if the class is defined to have a package a; then you need to import the class with the package name. If you have two packages which contain a class with the same name, then in your class which needs to invoke each of them, you will need to use a fully-qualified name. For example:
import a.Foo;
import b.Foo;
public class Bar
{
public static void main(String[] args)
{
a.Foo aFoo = new a.Foo();
b.Foo bFoo = new b.Foo();
}
}
Alternatively, if you have two packages with classes of the same name, you can simply skip importing them, but rather -- using them by their fully-qualified names (FQN-s).
If the class does not have a package ...;, then simply import it as:
import Foo;
However, if you have two packages (from different libraries) which contain classes with identical FQN-s, then the first one on the classpath will be picked.
Please, bear in mind that the convention for naming packages is to use lowercase letters and for classes -- the name should start with an upper case letter for each word in the class' name.

Yes it is possible.
If you have the following:
Package: PackA
Class: ClasA
Do:
import PackA.ClassA; //Import the class
OR
import PackA.*; //Import all the classes within the package

yes it is possible just import the package
syntax
import pck.ClassA or import pck.*

Yes, you have to use package syntax.
importing all class inside folder A.
import com.pack.A.*;
importing specific class inside folder A.
import com.pack.ClassName;

how to implement a java class so that it holds constants for other classes in other files

What is the best way to implement a system to establish program-wide constants? I have a program that spans several files and I want to have a class that stores constants so that they are available for all the other files.
I tried something like this:
in Constants.java
public final class Constants{
private Constants(){}
public static final String EX = "mas";
}
and in test.java
import Constants.*;
public class test{
public static void main( String[]args){
System.out.println( EX );
}
}
but I get the following error
test.java:1: error: cannot find symbol
import static Constants.*;
^
symbol: class Constants
Constants.java and test.java are in the same dir.

You can not import from the default package. See Java Language Specification
Put the class in a package.

You can't import classes without a package (also called the default package)

If these two classes are in the same package, you do not need to import.
Remove the import statement for Constants class
In your test class, use the following line: Constants.EX to get the value of EX.

You'll need to preface your reference to Constants in the import with the full package name.
For example, if Constants and test are in the package "com.mystuff", you'll need to import as follows:
import static com.mystuff.Constants.*;
Alternatively, since your classes are in the same package you don't really need the import at all - just qualify EX with the Constants class, e.g. Constants.EX instead of just EX.

Any public static final variable will be accessible anywhere without creating an instance of an object. In your case you can access the EX variable with:
Constants.EX;
In general with good object-oriented design the constants which you include in a class should be specific to that object type. For example if you have a Window object its constant might be "aspectRatio" or "height" but it would be inappropriate to have "nameOfUser" in a Window class as a constant. So sometimes making a "universal" Constants class will inherently make you lose sight of which variables truly belong in different classes when following object-oriented ideals.

parent package class accessible from child packge class in java?

In java parent package class accessible from child packge class? please explain me any one?
example
package A.A1.A2 contains class sub
package A contains class sup
Is there anyway to access sup from sub?
pls explain.
i tried import it won't work
Example:
before the program Directory Structure is
package1 contains package1.java --> package2 --> package3 contains PCheck.java
//package1.java
package package1;
public class package1{
public static void main(String[] args) {
}
}
class phelo{
phelo(){
int a;
System.out.println("hai fun freom package 1");
}
}
//PCheck.java;
package package1.package2.package3;
import package1.*; //to import package1.java
public class PCheck {
public static void main(String[] args) {
phelo obj=new phelo();
}
}
class helo{
helo(){
int a;
System.out.println("hai fun from package 3");
}
}
output:
compile time error:package package1.package2.package3 doesnot exist;
for import class from different directory we use import statements but here we need access parent package from subpackage.i tried import it won't work pls explain with an example.

Java does not recognize the notion of a subpackage1. As far as Java is concerned packages a and a.b and a.b.c are unrelated. They are just names.
So, if you want to access a.b.SomeClass from a.b.c.SomeOtherClass, you must either use a fully qualified class name, or add an import to SomeOtherClass
1 - From Java 9 onwards you can use modules to implement abstraction boundaries that are larger than a single package. This doesn't address this question which is about package-private access, but it could be viewed as an alternative to package-private.
As for your example that doesn't compile, I think we need a proper MCVE to understand that. My guess is that you have gotten the file organization for your source tree wrong ...
It is also possible that the problem is that the visibility of the class you are trying to import is wrong (package private), but that wouldn't cause the compiler to say that the package doesn't exist, like you said it does.

In java parent package class
accessible from child packge class?
please explain me any one?
Not the way you're thinking. The directories are hierarchical, but the packages are just distinguishing names.
If a child needs a parent package, or any other outside its hierarchy, it simply needs to import it.
That's why import foo.* doesn't give you access to all sub-package names - packages aren't hierarchical the way directories are.

All answers seem to miss OP's point on package class as everyone seem to suggest importing the class as a workaround.
The answer is: package-level classes (i.e., without explicit access level modifier), are visible ONLY for the EXACT same package.
https://docs.oracle.com/javase/tutorial/java/javaOO/accesscontrol.html
If a class has no modifier (the default, also known as package-private), it is visible only within its own package
This effectively means that neither parent/child/external packages can view the class.

In object of a.b.c.SomeOtherClass:
List<String> tmp=new ArrayList<String>(Arrays.asList(this.getClass().getPackage().getName().split("\\.")));
tmp.remove(tmp.size()-1);
String parent_package_name=tmp.toString().replace(", ", ".").replaceAll("[\\[\\]]", "");
Class cls=Class.forName(parent_package_name+".SomeClass");

Simply import it:
import A.sup;

Yes I have encountered the same error whenever I tried to access a class in the same package of the source file or the parent package of the source file it is generating a compiled time error , so by trial and error method I came to the conclusion that the packages are not built in a way to support main methods in the classes and they are not built in a way to support importing their parent packages or child packages

default class can be only used within package except subpackage