程序报错，求高人。

Internal error: (org.jdom.input.JDOMParseException) Error on line 60: The content of elements must consist of well-formed character data or markup.
org.jdom.input.JDOMParseException: Error on line 60: The content of elements must consist of well-formed character data or markup.
at org.jdom.input.SAXBuilder.build(SAXBuilder.java:504)
at org.jdom.input.SAXBuilder.build(SAXBuilder.java:888)
at com.intellij.openapi.util.JDOMUtil.loadDocument(JDOMUtil.java:374)
at com.intellij.openapi.util.JDOMUtil.loadDocument(JDOMUtil.java:352)
at org.jetbrains.jps.model.serialization.JpsLoaderBase.loadRootElement(JpsLoaderBase.java:66)
at org.jetbrains.jps.model.serialization.JpsLoaderBase.loadRootElement(JpsLoaderBase.java:39)
at org.jetbrains.jps.model.serialization.JpsProjectLoader.a(JpsProjectLoader.java:116)
at org.jetbrains.jps.model.serialization.JpsProjectLoader.loadProject(JpsProjectLoader.java:98)
at org.jetbrains.jps.model.serialization.impl.JpsSerializationManagerImpl.loadModel(JpsSerializationManagerImpl.java:41)
at org.jetbrains.jps.cmdline.JpsModelLoaderImpl.loadModel(JpsModelLoaderImpl.java:45)
at org.jetbrains.jps.cmdline.BuildRunner.load(BuildRunner.java:71)
at org.jetbrains.jps.cmdline.BuildSession.runBuild(BuildSession.java:196)
at org.jetbrains.jps.cmdline.BuildSession.run(BuildSession.java:112)
at org.jetbrains.jps.cmdline.BuildMain$MyMessageHandler$1.run(BuildMain.java:132)
at org.jetbrains.jps.service.impl.SharedThreadPoolImpl$1.run(SharedThreadPoolImpl.java:41)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: org.xml.sax.SAXParseException: The content of elements must consist of well-formed character data or markup.
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.startOfMarkup(Unknown Source) 
 
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
at org.jdom.input.SAXBuilder.build(SAXBuilder.java:489)
... 20 more
Caused by: org.xml.sax.SAXParseException: The content of elements must consist of well-formed character data or markup.
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.startOfMarkup(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
at org.jdom.input.SAXBuilder.build(SAXBuilder.java:489)
at org.jdom.input.SAXBuilder.build(SAXBuilder.java:888)
at com.intellij.openapi.util.JDOMUtil.loadDocument(JDOMUtil.java:374)
at com.intellij.openapi.util.JDOMUtil.loadDocument(JDOMUtil.java:352) 
 
at org.jetbrains.jps.model.serialization.JpsLoaderBase.loadRootElement(JpsLoaderBase.java:66)
at org.jetbrains.jps.model.serialization.JpsLoaderBase.loadRootElement(JpsLoaderBase.java:39)
at org.jetbrains.jps.model.serialization.JpsProjectLoader.a(JpsProjectLoader.java:116)
at org.jetbrains.jps.model.serialization.JpsProjectLoader.loadProject(JpsProjectLoader.java:98)
at org.jetbrains.jps.model.serialization.impl.JpsSerializationManagerImpl.loadModel(JpsSerializationManagerImpl.java:41)
at org.jetbrains.jps.cmdline.JpsModelLoaderImpl.loadModel(JpsModelLoaderImpl.java:45)
at org.jetbrains.jps.cmdline.BuildRunner.load(BuildRunner.java:71)
at org.jetbrains.jps.cmdline.BuildSession.runBuild(BuildSession.java:196)
at org.jetbrains.jps.cmdline.BuildSession.run(BuildSession.java:112)
at org.jetbrains.jps.cmdline.BuildMain$MyMessageHandler$1.run(BuildMain.java:132)
at org.jetbrains.jps.service.impl.SharedThreadPoolImpl$1.run(SharedThreadPoolImpl.java:41)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

[解决办法]
你看看你的xml文件格式对吗，好像是缺少了必要的 />或者</>对，就是你的元素没有封闭，要成对<a></a>
[解决办法]
你的Android platform for API level 16安装了吗？你是在解析xml吗？解析的api安装了吗？
A required class was missing while executing com.jayway.maven.plugins.android.generation2:android-maven-plugin:3.6.0:generate-sources: Lorg/sonatype/aether/RepositorySystem;
缺少一个必须的类