CentOS6.5 静默安装Oracle 11G过程中提示：Exception in thread “main” java.lang.NoClassDefFoundError .
在执行./runInstaller -silent -force -noconfig -responseFile /home/oracle/database/response/db_install.rsp时，提示：

$ Exception in thread "main" java.lang.NoClassDefFoundError
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:164)
        at java.awt.Toolkit$2.run(Toolkit.java:821)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.awt.Toolkit.getDefaultToolkit(Toolkit.java:804)
        at com.jgoodies.looks.LookUtils.isLowResolution(Unknown Source)
        at com.jgoodies.looks.LookUtils.<clinit>(Unknown Source)
        at com.jgoodies.looks.plastic.PlasticLookAndFeel.<clinit>(PlasticLookAndFeel.java:122)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:242)
        at javax.swing.SwingUtilities.loadSystemClass(SwingUtilities.java:1783)
        at javax.swing.UIManager.setLookAndFeel(UIManager.java:480)
        at oracle.install.commons.util.Application.startup(Application.java:758)
        at oracle.install.commons.flow.FlowApplication.startup(FlowApplication.java:164)
        at oracle.install.commons.flow.FlowApplication.startup(FlowApplication.java:181)
        at oracle.install.commons.base.driver.common.Installer.startup(Installer.java:265)
        at oracle.install.ivw.db.driver.DBInstaller.startup(DBInstaller.java:114)
        at oracle.install.ivw.db.driver.DBInstaller.main(DBInstaller.java:132)

解决方法：

1 .系统中设置了DISPLAY环境变量

[oracle@HOST database]$ echo $DISPLAY
localhost:11.0
[oracle@HOST database]$ unset DISPLAY
[oracle@HOST database]$ echo $DISPLAY

然后再执行./runInstaller -silent -force -noconfig -responseFile /home/oracle/database/response/db_install.rsp，执行成功

2.重新启动系统。以oracle的身份登录系统，然后执行./runInstaller -silent -force -noconfig -responseFile /home/oracle/database/response/db_install.rsp

我是通过第一种方法解决的。