导入 java.awt 无法解析

Question

I have installed the Eclipse [Version: Photon Release (4.8.0)] and JDK 10 on a MacBookPro with macOS 10.13.5 When I write in my code: import java.awt.*;

I get the error:

The import java.awt cannot be resolved

Is the java.awt included in JDK 10 ? If yes where is and how can I make visible to Eclipse? If no how can I add java.awt?

Answer 1

Is the java.awt included in JDK 10?

Ye, the package does exist. The Java10 API docs do confirm the same as well.

If yes where is and how can I make visible to Eclipse?

In a modular code, all you need to do, is to resolve the java.desktop module by declaring a dependency on it in your module-descriptor file( module-info.java ). ie

requires java.desktop;

Answer 2

Basically, just add this maven build compiler plugin portion to your main project Maven POM.xml
to specify which JDK9+ modules MUST BE added for javac compilation purposes.

  <?xml version="1.0" encoding="UTF-8"?>
  <project xmlns="http://maven.apache.org/POM/4.0.0" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    
    ...
    
    <properties>
        <java.version>11</java.version>
        ...
    </properties>

    ...

    <build>
        <plugins>
             <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>

                    <!-- JDK9+ Add Module MAGIC happens below...          -->
                    <!-- Add implicit default JDK9+ java.se explicitly    -->
                    <!-- Add explicit java.desktop for import java.awt.*; -->
                    <compilerArgs>
                        <arg>--add-modules</arg>
                        <arg>java.se,java.desktop</arg>
                    </compilerArgs>
                </configuration>
            </plugin>
        </plugins>
    </build>

  </project>

as explained here:

https://www.baeldung.com/java-9-modularity

For other common missing JDK10+ modules, please refer to:

http://cr.openjdk.java.net/~iris/se/10/pfd/java-se-10-pfd-spec-01/api/overview-summary.html

Answer 3

I have tried this, and in fact the error dissapears, but the program is unstable. I will try to do anything and it will randomly crash. I don't know what to do, but it just won't work, it's unusable.