我想尝试 Oracle 新 JDK 1.7 中推出的一些功能。我关注了以下帖子：-Oracle JDK 1.7但这篇文章似乎没有帮助。
我试图获取java.nio.file.Paths类文件的结构，但出现以下错误：-
buffer@ankit:~$ javap java.nio.file.Paths ERROR:Could not find java.nio.file.Paths
然而，我可以轻松获得有关 JAVA SE 1.6 之前的类结构的信息，下面是一个例子：-
buffer@ankit:~$ javap java.lang.Object
Compiled from "Object.java"
public class java.lang.Object{
public java.lang.Object();
public final native java.lang.Class getClass();
public native int hashCode();
public boolean equals(java.lang.Object);
protected native java.lang.Object clone() throws java.lang.CloneNotSupportedException;
public java.lang.String toString();
public final native void notify();
public final native void notifyAll();
public final native void wait(long) throws java.lang.InterruptedException;
public final void wait(long, int) throws java.lang.InterruptedException;
public final void wait() throws java.lang.InterruptedException;
protected void finalize() throws java.lang.Throwable;
static {};
}
运行 java -version 得到以下结果：-
buffer@ankit:~$ java -version java version "1.7.0_09" Java(TM) SE 运行时环境（build 1.7.0_09-b05）Java HotSpot(TM) 64 位服务器 VM（build 23.5-b02，混合模式）
系统信息
buffer@ankit:~$ sudo update-alternatives --config java
[sudo] password for buffer:
There are 4 choices for the alternative java (providing /usr/bin/java).
Selection Path Priority Status
------------------------------------------------------------
0 /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java 1061 auto mode
1 /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java 1061 manual mode
2 /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java 1051 manual mode
3 /usr/lib/jvm/jdk1.7.0_09/ 1 manual mode
* 4 /usr/lib/jvm/jdk1.7.0_09/bin/java 1 manual mode
buffer@ankit:~$ sudo update-alternatives --config javac
There are 2 choices for the alternative javac (providing /usr/bin/javac).
Selection Path Priority Status
------------------------------------------------------------
0 /usr/lib/jvm/java-6-openjdk-amd64/bin/javac 1061 auto mode
1 /usr/lib/jvm/java-6-openjdk-amd64/bin/javac 1061 manual mode
* 2 /usr/lib/jvm/jdk1.7.0_09/bin/javac 1 manual mode
buffer@ankit:~$ sudo update-alternatives --config javaws
There are 3 choices for the alternative javaws (providing /usr/bin/javaws).
Selection Path Priority Status
------------------------------------------------------------
0 /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/javaws 1061 auto mode
1 /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/javaws 1061 manual mode
2 /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/javaws 1060 manual mode
* 3 /usr/lib/jvm/jdk1.7.0_09/bin/javaws 1 manual mode
目录结构/usr/lib/jvm/如下：-
buffer@ankit:~$ ls -l /usr/lib/jvm/
total 24
lrwxrwxrwx 1 root root 24 Dec 2 2011 default-java -> java-1.6.0-openjdk-amd64
drwxr-xr-x 4 root root 4096 Nov 8 16:24 java-1.5.0-gcj-4.6
lrwxrwxrwx 1 root root 24 Dec 2 2011 java-1.6.0-openjdk -> java-1.6.0-openjdk-amd64
lrwxrwxrwx 1 root root 20 Oct 25 00:01 java-1.6.0-openjdk-amd64 -> java-6-openjdk-amd64
lrwxrwxrwx 1 root root 20 Oct 25 06:59 java-1.7.0-openjdk-amd64 -> java-7-openjdk-amd64
lrwxrwxrwx 1 root root 24 Dec 2 2011 java-6-openjdk -> java-1.6.0-openjdk-amd64
drwxr-xr-x 7 root root 4096 Nov 8 16:24 java-6-openjdk-amd64
drwxr-xr-x 3 root root 4096 Nov 8 16:24 java-6-openjdk-common
drwxr-xr-x 5 root root 4096 Nov 8 05:48 java-7-openjdk-amd64
drwxr-xr-x 3 root root 4096 Nov 8 05:48 java-7-openjdk-common
drwxr-xr-x 8 buffer buffer 4096 Sep 25 09:08 jdk1.7.0_09
任何帮助都将非常感激。
答案1
Java 可执行文件
Java 由许多单独的可执行文件组成 -javac并且javaws是最常见的。
javap另一个是 - 安装 Java 时，您需要单独确保每个可执行文件都已注册 - 您可以使用update-alternatives
sudo 更新替代方案 --install “/usr/bin/java” “javap” “/usr/lib/jvm/jdk1.7.0/bin/javap” 1 sudo 更新替代方案 --config javap
如果您希望在开发过程中使用它们，这个答案会为您提供可以注册的各个可执行文件的列表。
或者 - 您可以使用第三方 PPA，例如webupd8- 但作为开发人员，我喜欢了解问题并根据我的需要定制我的配置。
答案2
通过这个PPA安装
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java7-installer
http://www.webupd8.org/2012/01/install-oracle-java-jdk-7-in-ubuntu-via.html