C:\Users\jaina_000\Desktop\learn_java\p1>javac Testp1.java
Testp1.java:6: error: cannot find symbol
Protection ob = new Protection();
^
symbol: class Protection
location: class Testp1
Testp1.java:6: error: cannot find symbol
Protection ob = new Protection();
^
symbol: class Protection
location: class Testp1
Testp1.java:7: error: cannot find symbol
Derived ob1 = new Derived();
^
symbol: class Derived
location: class Testp1
Testp1.java:7: error: cannot find symbol
Derived ob1 = new Derived();
^
symbol: class Derived
location: class Testp1
Testp1.java:8: error: cannot find symbol
SamePackage ob2 = new SamePackage();
^
symbol: class SamePackage
location: class Testp1
Testp1.java:8: error: cannot find symbol
SamePackage ob2 = new SamePackage();
^
symbol: class SamePackage
location: class Testp1
6 errors
package p1;
public class Testp1
{
public static void main(String a[])
{
Protection ob = new Protection();
Derived ob1 = new Derived();
SamePackage ob2 = new SamePackage();
}
}
package p1;
public class Protection
{
int n = 1;
private int n_pri = 2;
protected int n_pro = 3;
public int n_pub = 4;
public Protection()
{
System.out.println("Inside base constructor.");
System.out.println(" n = "+n);
System.out.println("n_pri = "+n_pri);
System.out.println("n_pro = "+n_pro);
System.out.println("n_pub = "+n_pub);
}
}
package p1;
class Derived extends Protection
{
Derived()
{
System.out.println("Inside Derived constructor.");
System.out.println(" n = "+n);
// System.out.println("n_pri = "+n_pri);
System.out.println("n_pro = "+n_pro);
System.out.println("n_pub = "+n_pub);
}
}
package p1;
class SamePackage{
SamePackage(){
Protection p = new Protection();
System.out.println("Inside SamePackage constructor.");
System.out.println(" n = "+p.n);
// System.out.println("n_pri = "+p.n_pri);
System.out.println("n_pro = "+p.n_pro);
System.out.println("n_pub = "+p.n_pub);
}
}
1 回答
当你有包时，你不能像在没有包的类中那样简单地编译或运行 .
当你编译时，你需要导航到你的包文件夹之外，然后在你的情况下使用命令
javac [package]/[class].so编译它应该是javac p1/Testp1.java并且在运行时使用此命令
java[package.class]..so在您的情况下它应该是java p1.Testp1确保你不在包[p1]里面，你应该在包之外[通过cmd导航到文件夹learn_java后编译] .
最后这就是你的cmd的样子