Method binded to commandbutton never called due to javax.el.PropertyNotWritableException - jsf-2

Question

When I click the commandButton, it never goes in the binded method in the managed bean but an exception come:
javax.el.PropertyNotWritableException: /configuration.xhtml #22,73
value="#{configurationBean.maxResUse}": The class
'ch.morphean.videoaid.lb.managedBean.ConfigurationBean' does not have
a writable property 'maxResUse'.
ManagedBean:
public class ConfigurationBean {
private List<String> policy = new ArrayList<String>();
private int timeOut;
private String email;
private boolean secondary;
private short maxResUse;
private String selectedPolicy;
public String getSelectedPolicy() {
return selectedPolicy;
}
public void setSelectedPolicy(String selectedPolicy) {
this.selectedPolicy = selectedPolicy;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public boolean isSecondary() {
return secondary;
}
public void setSecondary(boolean secondary) {
this.secondary = secondary;
}
public int getMaxResUse() {
return maxResUse;
}
public void setMaxResUse(short maxResUse) {
this.maxResUse = maxResUse;
}
public int getTimeOut() {
return timeOut;
}
public void setTimeOut(int timeOut) {
this.timeOut = timeOut;
}
public List<String> getPolicy() {
return policy;
}
public void setPolicy(List<String> policy) {
this.policy = policy;
}
#PostConstruct
public void init() {
List<PolicyDTO> p = getPolicies();
for (PolicyDTO pdto : p) {
policy.add(pdto.getName());
}
ConfigurationResponse conf = getConfig();
this.email = conf.getEmailAlert();
this.maxResUse = conf.getMaxResUse();
this.timeOut = conf.getTimeOut();
}
public String saveConfig() {
System.out.println("action");
configuration.xhtml:
<f:view>
<h:form>
<h:panelGrid columns="2">
<h:outputLabel value="Balancing policy" />
<h:selectOneListbox value="#{configurationBean.selectedPolicy}">
<f:selectItems value="#{configurationBean.policy}" />
</h:selectOneListbox>
<h:outputLabel value="Time out (ms)" />
<h:inputText value="#{configurationBean.timeOut}" />
<h:outputLabel value="maximum use ressource %" />
<h:inputText maxlength="2" value="#{configurationBean.maxResUse}" />
<h:outputLabel value="Secondary" />
<h:selectBooleanCheckbox value="#{configurationBean.secondary}" />
<h:outputLabel value="Email alert" />
<h:inputText value="#{configurationBean.email}" />
<h:commandButton action="#{configurationBean.saveConfig}"
value="start" />
</h:panelGrid>
</h:form>
</f:view>
faces-config:
<managed-bean>
<managed-bean-name>configurationBean</managed-bean-name>
<managed-bean-class>ch.morphean.videoaid.lb.managedBean.ConfigurationBean</managed-bean-class>
<managed-bean-scope>session</managed-bean-scope>
</managed-bean>
thanks for the help