Firstly I changed the contact id to be a primitive int rather than an Integer
(This only reproduces with primitive id properties).

public void test() {
        
        Customer c = new Customer();
        c.setName("testll");
        
        Ebean.save(c);
        
        Customer c1 = Ebean.find(Customer.class)
            .setAutofetch(false)
            .select("id")
            .join("contacts","id")
            .where().idEq(c.getId())
            .findUnique();
        
        List<Contact> contacts = c1.getContacts();
        int sz = contacts.size();
        
        Assert.assertTrue(sz == 0);
    }

More stack trace is:

javax.persistence.PersistenceException: Error readSet on com.imilia.server.domain.common.PhoneContact.oid
at com.avaje.ebean.server.deploy.BeanProperty.readSet(BeanProperty.java:464)
at com.avaje.ebean.server.deploy.id.IdBinderSimple.readSet(IdBinderSimple.java:109)
at com.avaje.ebean.server.query.SqlTreeNodeBean.load(SqlTreeNodeBean.java:224)
at com.avaje.ebean.server.query.SqlTreeNodeManyRoot.load(SqlTreeNodeManyRoot.java:30)
at com.avaje.ebean.server.query.SqlTreeNodeBean.load(SqlTreeNodeBean.java:290)
at com.avaje.ebean.server.query.CQuery.readRow(CQuery.java:557)
at com.avaje.ebean.server.query.CQuery.readBeanInternal(CQuery.java:594)
at com.avaje.ebean.server.query.CQuery.readTheRows(CQuery.java:675)
at com.avaje.ebean.server.query.CQuery.readCollection(CQuery.java:660)
at com.avaje.ebean.server.query.CQueryEngine.findMany(CQueryEngine.java:166)
at com.avaje.ebean.server.query.DefaultOrmQueryEngine.findMany(DefaultOrmQueryEngine.java:88)
at com.avaje.ebean.server.core.OrmQueryRequest.findList(OrmQueryRequest.java:277)
at com.avaje.ebean.server.core.DefaultServer.findList(DefaultServer.java:1280)
at com.avaje.ebean.server.core.DefaultBeanLoader.loadMany(DefaultBeanLoader.java:143)
at com.avaje.ebean.server.core.DefaultServer.loadMany(DefaultServer.java:370)
at com.avaje.ebean.server.loadcontext.DLoadManyContext.loadMany(DLoadManyContext.java:143)
at com.avaje.ebean.common.AbstractBeanCollection.lazyLoadCollection(AbstractBeanCollection.java:140)
at com.avaje.ebean.common.BeanSet.init(BeanSet.java:110)
at com.avaje.ebean.common.BeanSet.iterator(BeanSet.java:234)
at com.imilia.server.service.impl.AddressServiceImpl.save(AddressServiceImpl.java:34)
at com.imilia.server.service.impl.AddressServiceImpl.save(AddressServiceImpl.java:21)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy43.save(Unknown Source)
at com.imilia.server.service.impl.PersonServiceImpl.save(PersonServiceImpl.java:29)
at com.imilia.server.service.impl.PersonServiceImpl.save(PersonServiceImpl.java:19)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:198)
at $Proxy44.save(Unknown Source)
at com.imilia.bkf.service.impl.SubscriptionServiceImpl.saveSubscriptionPersonAddress(SubscriptionServiceImpl.java:51)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy45.saveSubscriptionPersonAddress(Unknown Source)
at com.imilia.bkf.service.SubscriptionServiceTest.testSaveSubscriptons(SubscriptionServiceTest.java:81)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at org.springframework.test.context.junit4.SpringTestMethod.invoke(SpringTestMethod.java:160)
at org.springframework.test.context.junit4.SpringMethodRoadie.runTestMethod(SpringMethodRoadie.java:233)
at org.springframework.test.context.junit4.SpringMethodRoadie$RunBeforesThenTestThenAfters.run(SpringMethodRoadie.java:333)
at org.springframework.test.context.junit4.SpringMethodRoadie.runWithRepetitions(SpringMethodRoadie.java:217)
at org.springframework.test.context.junit4.SpringMethodRoadie.runTest(SpringMethodRoadie.java:197)
at org.springframework.test.context.junit4.SpringMethodRoadie.run(SpringMethodRoadie.java:143)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.invokeTestMethod(SpringJUnit4ClassRunner.java:160)
at org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:51)
at org.junit.internal.runners.JUnit4ClassRunner$1.run(JUnit4ClassRunner.java:44)
at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:27)
at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:37)
at org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:97)
at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:62)
at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.executeTestSet(AbstractDirectoryTestSuite.java:140)
at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.execute(AbstractDirectoryTestSuite.java:127)
at org.apache.maven.surefire.Surefire.run(Surefire.java:177)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at org.apache.maven.surefire.booter.SurefireBooter.runSuitesInProcess(SurefireBooter.java:345)
at org.apache.maven.surefire.booter.SurefireBooter.main(SurefireBooter.java:1009)
Caused by: java.lang.RuntimeException: set oid on [com.imilia.server.domain.common.PhoneContact] arg[null] type[com.imilia.server.domain.common.PhoneContact] threw error
at com.avaje.ebean.server.deploy.BeanProperty.setValue(BeanProperty.java:601)
at com.avaje.ebean.server.deploy.BeanProperty.readSet(BeanProperty.java:459)
... 80 more
Caused by: java.lang.NullPointerException
at com.imilia.server.domain.common.PhoneContact._ebean_setField(PhoneContact.java:1)
at com.avaje.ebean.server.reflect.EnhanceBeanReflect$Setter.set(EnhanceBeanReflect.java:118)
at com.avaje.ebean.server.deploy.BeanProperty.setValue(BeanProperty.java:592)
... 81 more

testSaveAddress(com.imilia.bkf.service.SubscriptionServiceTest) Time elapsed: 0.008 sec <<< ERROR!
javax.persistence.PersistenceException: Error readSet on com.imilia.server.domain.common.PhoneContact.oid
at com.avaje.ebean.server.deploy.BeanProperty.readSet(BeanProperty.java:464)
at com.avaje.ebean.server.deploy.id.IdBinderSimple.readSet(IdBinderSimple.java:109)
at com.avaje.ebean.server.query.SqlTreeNodeBean.load(SqlTreeNodeBean.java:224)
at com.avaje.ebean.server.query.SqlTreeNodeManyRoot.load(SqlTreeNodeManyRoot.java:30)
at com.avaje.ebean.server.query.SqlTreeNodeBean.load(SqlTreeNodeBean.java:290)
at com.avaje.ebean.server.query.CQuery.readRow(CQuery.java:557)
at com.avaje.ebean.server.query.CQuery.readBeanInternal(CQuery.java:594)
at com.avaje.ebean.server.query.CQuery.readTheRows(CQuery.java:675)
at com.avaje.ebean.server.query.CQuery.readCollection(CQuery.java:660)
at com.avaje.ebean.server.query.CQueryEngine.findMany(CQueryEngine.java:166)
at com.avaje.ebean.server.query.DefaultOrmQueryEngine.findMany(DefaultOrmQueryEngine.java:88)
at com.avaje.ebean.server.core.OrmQueryRequest.findList(OrmQueryRequest.java:277)
at com.avaje.ebean.server.core.DefaultServer.findList(DefaultServer.java:1280)
at com.avaje.ebean.server.core.DefaultBeanLoader.loadMany(DefaultBeanLoader.java:143)
at com.avaje.ebean.server.core.DefaultServer.loadMany(DefaultServer.java:370)
at com.avaje.ebean.server.loadcontext.DLoadManyContext.loadMany(DLoadManyContext.java:143)
at com.avaje.ebean.common.AbstractBeanCollection.lazyLoadCollection(AbstractBeanCollection.java:140)
at com.avaje.ebean.common.BeanSet.init(BeanSet.java:110)
at com.avaje.ebean.common.BeanSet.iterator(BeanSet.java:234)
at com.imilia.server.service.impl.AddressServiceImpl.save(AddressServiceImpl.java:34)
at com.imilia.server.service.impl.AddressServiceImpl.save(AddressServiceImpl.java:21)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy43.save(Unknown Source)
at com.imilia.bkf.service.SubscriptionServiceTest.testSaveAddress(SubscriptionServiceTest.java:100)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at org.springframework.test.context.junit4.SpringTestMethod.invoke(SpringTestMethod.java:160)
at org.springframework.test.context.junit4.SpringMethodRoadie.runTestMethod(SpringMethodRoadie.java:233)
at org.springframework.test.context.junit4.SpringMethodRoadie$RunBeforesThenTestThenAfters.run(SpringMethodRoadie.java:333)
at org.springframework.test.context.junit4.SpringMethodRoadie.runWithRepetitions(SpringMethodRoadie.java:217)
at org.springframework.test.context.junit4.SpringMethodRoadie.runTest(SpringMethodRoadie.java:197)
at org.springframework.test.context.junit4.SpringMethodRoadie.run(SpringMethodRoadie.java:143)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.invokeTestMethod(SpringJUnit4ClassRunner.java:160)
at org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:51)
at org.junit.internal.runners.JUnit4ClassRunner$1.run(JUnit4ClassRunner.java:44)
at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:27)
at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:37)
at org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:97)
at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:62)
at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.executeTestSet(AbstractDirectoryTestSuite.java:140)
at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.execute(AbstractDirectoryTestSuite.java:127)
at org.apache.maven.surefire.Surefire.run(Surefire.java:177)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at org.apache.maven.surefire.booter.SurefireBooter.runSuitesInProcess(SurefireBooter.java:345)
at org.apache.maven.surefire.booter.SurefireBooter.main(SurefireBooter.java:1009)
Caused by: java.lang.RuntimeException: set oid on [com.imilia.server.domain.common.PhoneContact] arg[null] type[com.imilia.server.domain.common.PhoneContact] threw error
at com.avaje.ebean.server.deploy.BeanProperty.setValue(BeanProperty.java:601)
at com.avaje.ebean.server.deploy.BeanProperty.readSet(BeanProperty.java:459)
... 59 more
Caused by: java.lang.NullPointerException
at com.imilia.server.domain.common.PhoneContact._ebean_setField(PhoneContact.java:1)
at com.avaje.ebean.server.reflect.EnhanceBeanReflect$Setter.set(EnhanceBeanReflect.java:118)
at com.avaje.ebean.server.deploy.BeanProperty.setValue(BeanProperty.java:592)
... 60 more

The issue ... is specific to primitive id properties.

Specifically when we read from the resultSet we can always get a null (even for int and long etc). The fix is for IdBinders to specifically check for the case of trying to set null ids.

Fixed in HEAD.