Doubt with beans usage

Question

Hi, I created a class MyClass. MyClass has a member of type MyObject.
MyObject has a member of type int and other of type ResultSet.
In the jsp file is used MyClass with scope=page with <jsp:jsp:useBean tag. If I try to access the int member of MyObject, through MyClass, there is no problem, but if I attempt to access the ResultSet member of MyObject through MyClass, it throws me the NullPointerException (I think that happens because the ResultSet member is null).
So, Java beans only "keep alive" the primitive and String members in the specified scope?

Answer 1

I tested your code on a simpler case, and it appears that one cannot access a property from a JavaBean if that property is not a primitive type.
Here's the simplified code:
TestJavaBean is the main JavaBean that contains a primitive type and an object type Rose.
package test10;
public class TestJavaBean {
   Rose rose;
   String someString;
    public TestJavaBean() {
    public Rose getRose() {
        return rose;
    public void setRose(Rose rose) {
        this.rose = rose;
    public String getSomeString() {
        return someString;
    public void setSomeString(String someString) {
        this.someString = someString;
}Here's the definition of the Rose JavaBean:
package test10;
public class Rose {
    int a;
    String b;
    public Rose() {
    public int getA() {
        return a;
    public void setA(int a) {
        this.a = a;
    public String getB() {
        return b;
    public void setB(String b) {
        this.b = b;
}Here's the JSP code that tries to refer to the embeded Rose object
  <jsp:useBean id="testJavaBean" class="test10.TestJavaBean"/>
  <%--
  <jsp:useBean id="rose" class="test10.Rose"/>
  <jsp:setProperty name="rose" property="a" value="123"/>
  <jsp:setProperty name="rose" property="b" value="'Value of b'"/>
  <jsp:setProperty name="testJavaBean" property="rose" value="roseObject"/>
  --%>
  <jsp:setProperty name="testJavaBean" property="someString" value="'Hello World!'"/>
  <%--
  <jsp:getProperty name="testJavaBean" property="rose"/>
  --%>
  <jsp:getProperty name="testJavaBean" property="someString"/>Some part of the above code in the JSP is commented out on purpose. When that code is uncommented I get:
org.apache.jasper.JasperException: jsp.error.beans.property.conversion
This means that one cannot access an object property from a JavaBean?
Or are JavaBeans not supposed to have object properties?
Or is it a bad practice to try to access a Java object from a JavaBean even though it is defined as a property of the bean?