Non parseable POM causing Maven build, installs to fail - eclipse

Question

I am unable to run Maven configuration using my Eclipse IDE hosted on my Mac. It keeps on failing with the message that it is unable to parse a maven enforcer plugin file (see message below). There has not been any change to my Eclipse environment, my Maven project, my Maven configuration or my POM file. This was working fine 3-4 months back. Yesterday I cleaned up my entire repository (under $home/.m2) folder along with files under it and after that I am getting this error. It appears the maven download process is encountering issue. My eclipse plugin (m2e) uses version 1.10. I know it is a maven related issue but any help will be greatly appreciated
[DEBUG] === REACTOR BUILD PLAN ================================================
[DEBUG] Project: fda-spl-fhir:fda-spl-fhir:war:3.8.0
[DEBUG] Tasks: [install]
[DEBUG] Style: Regular
[DEBUG] =======================================================================
[INFO]
[INFO] ---------------------< fda-spl-fhir:fda-spl-fhir >----------------------
[INFO] Building HAPI FHIR JPA Server - Starter Project 3.8.0
[INFO] --------------------------------[ war ]---------------------------------
[DEBUG] Lifecycle default -> [validate, initialize, generate-sources, process-sources, generate-resources, process-resources, compile, process-classes, generate-test-sources, process-test-sources, generate-test-resources, process-test-resources, test-compile, process-test-classes, test, prepare-package, package, pre-integration-test, integration-test, post-integration-test, verify, install, deploy]
[DEBUG] Lifecycle clean -> [pre-clean, clean, post-clean]
[DEBUG] Lifecycle site -> [pre-site, site, post-site, site-deploy]
[WARNING] The POM for org.apache.maven.plugins:maven-enforcer-plugin:jar:3.0.0-M2 is invalid, transitive dependencies (if any) will not be available: 1 problem was encountered while building the effective model
[FATAL] Non-parseable POM /Users/XXXXXX/.m2/repository/org/apache/maven/plugins/maven-enforcer-plugin/3.0.0-M2/maven-enforcer-plugin-3.0.0-M2.pom: entity reference name can not contain character =' (position: START_TAG seen ...com/main?ParticipantID=euekiz39ksg8nwp7iqj2fp5wzfwi5q76&FailedURI=... #1:270) # line 1, column 270
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.220 s
[INFO] Finished at: 2020-02-06T13:38:42-05:00
[INFO] ------------------------------------------------------------------------
[ERROR] Plugin org.apache.maven.plugins:maven-enforcer-plugin:3.0.0-M2 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-enforcer-plugin:jar:3.0.0-M2: 1 problem was encountered while building the effective model
[ERROR] [FATAL] Non-parseable POM /Users/XXXXXX/.m2/repository/org/apache/maven/plugins/maven-enforcer-plugin/3.0.0-M2/maven-enforcer-plugin-3.0.0-M2.pom: entity reference name can not contain character =' (position: START_TAG seen ...com/main?ParticipantID=euekiz39ksg8nwp7iqj2fp5wzfwi5q76&FailedURI=... #1:270) # line 1, column 270
[ERROR] -> [Help 1]
org.apache.maven.plugin.PluginResolutionException: Plugin org.apache.maven.plugins:maven-enforcer-plugin:3.0.0-M2 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-enforcer-plugin:jar:3.0.0-M2
at org.apache.maven.plugin.internal.DefaultPluginDependenciesResolver.resolve(DefaultPluginDependenciesResolver.java:117)
at org.apache.maven.plugin.internal.DefaultMavenPluginManager.getPluginDescriptor(DefaultMavenPluginManager.java:181)
at org.apache.maven.plugin.internal.DefaultMavenPluginManager.getMojoDescriptor(DefaultMavenPluginManager.java:286)
at org.apache.maven.plugin.DefaultBuildPluginManager.getMojoDescriptor(DefaultBuildPluginManager.java:244)
at org.apache.maven.lifecycle.internal.DefaultLifecycleMappingDelegate.calculateLifecycleMappings(DefaultLifecycleMappingDelegate.java:115)
at org.apache.maven.lifecycle.internal.DefaultLifecycleExecutionPlanCalculator.calculateLifecycleMappings(DefaultLifecycleExecutionPlanCalculator.java:265)
at org.apache.maven.lifecycle.internal.DefaultLifecycleExecutionPlanCalculator.calculateMojoExecutions(DefaultLifecycleExecutionPlanCalculator.java:216)
at org.apache.maven.lifecycle.internal.DefaultLifecycleExecutionPlanCalculator.calculateExecutionPlan(DefaultLifecycleExecutionPlanCalculator.java:126)
at org.apache.maven.lifecycle.internal.DefaultLifecycleExecutionPlanCalculator.calculateExecutionPlan(DefaultLifecycleExecutionPlanCalculator.java:144)
at org.apache.maven.lifecycle.internal.builder.BuilderCommon.resolveBuildPlan(BuilderCommon.java:96)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:110)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:56)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:305)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:192)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:105)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:956)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:290)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:194)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.eclipse.aether.resolution.ArtifactDescriptorException: Failed to read artifact descriptor for org.apache.maven.plugins:maven-enforcer-plugin:jar:3.0.0-M2
at org.apache.maven.repository.internal.DefaultArtifactDescriptorReader.loadPom(DefaultArtifactDescriptorReader.java:332)
at org.apache.maven.repository.internal.DefaultArtifactDescriptorReader.readArtifactDescriptor(DefaultArtifactDescriptorReader.java:192)
at org.eclipse.aether.internal.impl.DefaultRepositorySystem.readArtifactDescriptor(DefaultRepositorySystem.java:253)
at org.apache.maven.plugin.internal.DefaultPluginDependenciesResolver.resolve(DefaultPluginDependenciesResolver.java:103)
... 27 more
Caused by: org.apache.maven.model.building.ModelBuildingException: 1 problem was encountered while building the effective model
[FATAL] Non-parseable POM /Users/XXXXXX/.m2/repository/org/apache/maven/plugins/maven-enforcer-plugin/3.0.0-M2/maven-enforcer-plugin-3.0.0-M2.pom: entity reference name can not contain character =' (position: START_TAG seen ...com/main?ParticipantID=euekiz39ksg8nwp7iqj2fp5wzfwi5q76&FailedURI=... #1:270) # line 1, column 270
at org.apache.maven.model.building.DefaultModelProblemCollector.newModelBuildingException(DefaultModelProblemCollector.java:197)
at org.apache.maven.model.building.DefaultModelBuilder.readModel(DefaultModelBuilder.java:582)
at org.apache.maven.model.building.DefaultModelBuilder.build(DefaultModelBuilder.java:276)
at org.apache.maven.repository.internal.DefaultArtifactDescriptorReader.loadPom(DefaultArtifactDescriptorReader.java:314)
... 30 more
[ERROR]
[ERROR]
Thanks in advance for your help

Answer 1

As you probably know, Maven uses HTTP/HTTPS to fetch remote dependencies.
Sometimes the Maven repository that it uses is available only when you are connected to a VPN, or is otherwise sometimes unreachable. For example, your employer may have a private Maven repository that works when you're at work, but is unreachable at home.
Some Internet service providers (wrongly) do not return 404 error codes when you ask your browser to locate an unreachable URL. Instead, they return an HTML page with ads or other stuff on it that "help" you try to locate what you were looking for.
When you put all of these concepts together, if Maven uses HTTP to try to fetch a dependency from an unreachable Maven repository URL, it will fetch a page of HTML instead. In your case, you can see from your error message that there is something in that .pom file that looks like perhaps this is what happened.
The solution is to remove the containing directory from your local Maven cache (e.g. /Users/XXXXXX/.m2/repository/org/apache/maven/plugins/maven-enforcer-plugin/) and run Maven again when you know that you have a reliable network connection.