"Missing system library" while browsing code

[datho7561]

Sometimes when browsing code, I get "Missing system library" with the following stacktrace

java.lang.IllegalStateException: Missing system library
	at org.eclipse.jdt.core.dom.ASTParser.checkForSystemLibrary(ASTParser.java:311)
	at org.eclipse.jdt.core.dom.ASTParser.getClasspath(ASTParser.java:269)
	at org.eclipse.jdt.core.dom.ASTParser.internalCreateASTCached(ASTParser.java:1395)
	at org.eclipse.jdt.core.dom.ASTParser.lambda$1(ASTParser.java:1274)
	at org.eclipse.jdt.internal.core.JavaModelManager.cacheZipFiles(JavaModelManager.java:5708)
	at org.eclipse.jdt.core.dom.ASTParser.internalCreateAST(ASTParser.java:1274)
	at org.eclipse.jdt.core.dom.ASTParser.createAST(ASTParser.java:918)
	at org.eclipse.jdt.internal.core.search.indexing.SourceIndexer.resolveDocumentDomImpl(SourceIndexer.java:209)
	at org.eclipse.jdt.internal.core.search.indexing.SourceIndexer.resolveDocument(SourceIndexer.java:165)
	at org.eclipse.jdt.internal.core.search.JavaSearchParticipant.resolveDocument(JavaSearchParticipant.java:125)
	at org.eclipse.jdt.internal.core.search.indexing.IndexManager.indexResolvedDocument(IndexManager.java:668)
	at org.eclipse.jdt.internal.core.search.indexing.IndexManager$2.execute(IndexManager.java:1272)
	at org.eclipse.jdt.internal.core.search.processing.JobManager.indexerLoop(JobManager.java:541)
	at java.base/java.lang.Thread.run(Thread.java:1447)