Project not detected by Eclipse as a Java project

Some of the projects that were imported into eclipse were not detected by Eclipse as a Java project, and the upper-left corner of the project directory has no J-letters, which should be. Project is not configured, you need to configure a plug-in for this project, as follows:

<?xml version= "1.0" encoding= "UTF-8"?><projectdescription> <name>test1</name> <comment >no_m2eclipse_support:project files created with the Maven-eclipse-plugin is not supported in M2eclipse.</comment > <projects/> <buildSpec> <buildCommand> <name>org.eclipse.jdt.core.javabuilder</n ame> </buildCommand> </buildSpec> <natures> <nature>org.eclipse.jdt.core.javanature< /nature> </natures></projectDescription>

With the Org.eclipse.jdt.core.javanature plugin, eclipse can detect

Project not detected by Eclipse as a Java project