test/gc/test/gc/6845368/bigobj.java in the hotspot repo includes a class with close to 64K fields. javac takes several minutes to compile this file on slower machines. Sample output from collect/er_print:

Functions sorted by metric: Exclusive User CPU Time

Excl. User CPU Incl. User CPU Name
                                       
   sec. % sec. %
166.506 100.00 166.506 100.00 <Total>
 94.656 56.85 95.837 57.56 com.sun.tools.javac.code.Scope.lookup(com.sun.tools.javac.util.Name)
 57.200 34.35 57.200 34.35 com.sun.tools.javac.code.Scope$Entry.next()
  5.794 3.48 5.794 3.48 <JVM-System>
  1.181 0.71 1.181 0.71 com.sun.tools.javac.code.Scope$Entry.access$000(com.sun.tools.javac.code.Scope$Entry)
  0.220 0.13 0.220 0.13 <Unknown>
  0.200 0.12 112.809 67.75 com.sun.tools.javac.comp.Check.checkConflicts(com.sun.tools.javac.util.JCDiagnostic$DiagnosticPosition, com.sun.tools.javac.code.Symbol, com.sun.tools.javac.code.Symbol$TypeSymbol)
  0.180 0.11 0.440 0.26 com.sun.tools.javac.parser.Scanner.scanIdent()
  0.170 0.10 0.170 0.10 com.sun.tools.javac.util.List.nonEmpty()
  0.160 0.10 41.099 24.68 com.sun.tools.javac.comp.MemberEnter.visitVarDef(com.sun.tools.javac.tree.JCTree$JCVariableDecl)