我正试图把一个包含1048578个文件的目录复制到 hdfs 文件系统，但出现以下错误：

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Arrays.java:2367)
    at java.lang.AbstractStringBuilder.expandCapacity(AbstractStringBuilder.java:130)
    at java.lang.AbstractStringBuilder.ensureCapacityInternal(AbstractStringBuilder.java:114)
    at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:415)
    at java.lang.StringBuffer.append(StringBuffer.java:237)
    at java.net.URI.appendSchemeSpecificPart(URI.java:1892)
    at java.net.URI.toString(URI.java:1922)
    at java.net.URI.<init>(URI.java:749)
    at org.apache.hadoop.fs.shell.PathData.stringToUri(PathData.java:565)
    at org.apache.hadoop.fs.shell.PathData.<init>(PathData.java:151)
    at org.apache.hadoop.fs.shell.PathData.getDirectoryContents(PathData.java:273)
    at org.apache.hadoop.fs.shell.Command.recursePath(Command.java:347)
    at org.apache.hadoop.fs.shell.CommandWithDestination.recursePath(CommandWithDestination.java:291)
    at org.apache.hadoop.fs.shell.Command.processPaths(Command.java:308)
    at org.apache.hadoop.fs.shell.Command.processPathArgument(Command.java:278)
    at org.apache.hadoop.fs.shell.CommandWithDestination.processPathArgument(CommandWithDestination.java:243)
    at org.apache.hadoop.fs.shell.Command.processArgument(Command.java:260)
    at org.apache.hadoop.fs.shell.Command.processArguments(Command.java:244)
    at org.apache.hadoop.fs.shell.CommandWithDestination.processArguments(CommandWithDestination.java:220)
    at org.apache.hadoop.fs.shell.CopyCommands$Put.processArguments(CopyCommands.java:267)
    at org.apache.hadoop.fs.shell.Command.processRawArguments(Command.java:190)
    at org.apache.hadoop.fs.shell.Command.run(Command.java:154)
    at org.apache.hadoop.fs.FsShell.run(FsShell.java:287)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:84)
    at org.apache.hadoop.fs.FsShell.main(FsShell.java:340)