Can't create output stream on Tomcat 7

When I visit my web application on newly installed Tomcat 7, a message shows up:

SEVERE:
org.zkoss.zk.ui.UiException: javax.imageio.IIOException: Can't create output str
eam!
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstruct
orAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingC
onstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        ...

        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpo
int.java:2442)
        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoin
t.java:2431)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor
.java:908)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskTh
read.java:61)
        at java.lang.Thread.run(Thread.java:662)
Caused by: javax.imageio.IIOException: Can't create output stream!
        at javax.imageio.ImageIO.write(ImageIO.java:1560)
        at org.jfree.chart.encoders.SunPNGEncoderAdapter.encode(SunPNGEncoderAda
pter.java:127)
        at org.jfree.chart.encoders.SunPNGEncoderAdapter.encode(SunPNGEncoderAda
pter.java:108)
        at org.jfree.chart.encoders.EncoderUtil.encode(EncoderUtil.java:83)
        at org.zkoss.zkex.zul.impl.JFreeChartEngine.drawChart(JFreeChartEngine.j
ava:498)
        ... 33 more
Caused by: javax.imageio.IIOException: Can't create cache file!
        at javax.imageio.ImageIO.createImageOutputStream(ImageIO.java:397)
        at javax.imageio.ImageIO.write(ImageIO.java:1558)
        ... 37 more
Caused by: java.io.IOException: The system cannot find the path specified
        at java.io.WinNTFileSystem.createFileExclusively(Native Method)
        at java.io.File.checkAndCreate(File.java:1704)
        at java.io.File.createTempFile(File.java:1792)
        at javax.imageio.stream.FileCacheImageOutputStream.<init>(FileCacheImage
OutputStream.java:71)
        at com.sun.imageio.spi.OutputStreamImageOutputStreamSpi.createOutputStre
amInstance(OutputStreamImageOutputStreamSpi.java:50)
        at javax.imageio.ImageIO.createImageOutputStream(ImageIO.java:393)
        ... 38 more

Refer to http://java-monitor.com/forum/showthread.php?t=417
Some Tomcat installations do not have their temp folder created. Just create a “temp” under tomcat’s root folder.