Null Pointer Exception Traced to Line 90 of CommentPostgres.java, SQL works correctly in DBeaver, Test does not - amazon-rds

Question

All code for entire project is available here
The database is PostgreSQL 12.7
The backend is Java 11.0.12
I am building my TDD tests with JUnit 5.8.1
Here is CommentDaoTest.java
None of it is working, but I am specifically working on getAllNotNull
Line one of the method gets an exception response that leads to a NullPointerException on line 90 of CommentPostgres.java
package com.revature.data;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotEquals;
import java.util.Set;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import com.revature.beans.Comment;
import com.revature.data.postgres.CommentPostgres;
public class CommentDaoTest {
private CommentDAO cd = new CommentPostgres();
#BeforeEach
public void setup()
{
cd = new CommentPostgres();
}
#Test
public void getByIdNotNull()
{
Comment actual = cd.getById(1);
assertNotEquals(null, actual);
}
#Test
public void getByIdValidComment()
{
String expected = "Polarised methodical access";
Comment one = cd.getById(1);
String actual = one.getCommentText();
assertEquals(expected, actual);
}
#Test
public void getAllNotNull()
{
Set<Comment> actual = cd.getAll();
assertNotEquals(null, actual);
}
}
Here is the relevant part of CommentPostgres.java...
#Override
public Set<Comment> getAll() {
Set<Comment> comments = new HashSet<>();
try (Connection conn = connUtil.getConnection()) {
String sql = "select * from comment";
Statement stmt = conn.createStatement();
ResultSet resultSet = stmt.executeQuery(sql);
while (resultSet.next()) {
Comment comment = new Comment();
comment.setCommentId(resultSet.getInt("comment_id"));
comment.setCommentText(resultSet.getString("comment_text"));
**Line 90** comment.getApprover().setEmpId(resultSet.getInt("approver_id"));
comment.getRequest().setReqId(resultSet.getInt("req_id"));
comment.setSentAt(resultSet.getTimestamp("sent_at").toLocalDateTime());
System.out.println(comment);
comments.add(comment);
}
} catch (SQLException e) {
e.printStackTrace();
}
return comments;
}
Here is the relevant SQL
create table if not exists employee (
emp_id serial unique primary key,
first_name varchar(40),
last_name varchar(40),
username varchar(30),
passwd varchar(25),
role_id integer not null references user_role,
funds real,
supervisor_id integer,
dept_id integer
);
create table if not exists reimbursement (
req_id serial unique primary key,
emp_id integer references employee,
event_date date,
event_time time,
location varchar(50),
description varchar(75),
cost real,
grading_format_id integer references grading_format,
event_type_id integer references event_type,
status_id integer references status,
submitted_at time
);
create table if not exists comment (
comment_id serial unique primary key,
req_id integer references reimbursement,
approver_id integer references employee,
comment_text varchar(100),
sent_at time
);
INSERT INTO comment
(req_id, approver_id, comment_text, sent_at)
VALUES
(1, 43, 'Polarised methodical access', '8:56:03'),
(2, 34, 'Decentralized 3rd generation encryption', '16:26:13'),
(3, 1, 'Open-architected asymmetric firmware', '3:52:08'),
(4, 34, 'Upgradable content-based synergy', '8:01:03'),
(6, 49, 'Progressive foreground frame', '7:35:55'),
(7, 43, 'Persevering didactic definition', '16:55:07'),
(8, 43, 'Proactive responsive success', '2:21:47'),
(9, 17, 'Devolved content-based task-force', '22:04:18'),
(10, 43, 'Self-enabling client-server orchestration', '9:03:46'),
(13, 49, 'Pre-emptive stable encoding', '12:47:36'),
(14, 11, 'Streamlined asymmetric initiative', '17:45:58'),
(15, 43, 'Open-architected web-enabled leverage', '2:19:17'),
(17, 43, 'Innovative transitional alliance', '12:43:29'),
(19, 1, 'Organized didactic protocol', '3:54:43'),
(20, 17, 'Switchable 5th generation solution', '20:54:12');
The scripts holding the rest of it are on github in the link at the top.
When I do a
SELECT * FROM comment;
in DBeaver I get all of the comments with approver_id's
however when I run getAllNotNull I get a NullPointer pointing at the approver_id. I put a Sys.out trying to catch to comment a few lines below 90, but it doesn't hit so the NullPointer is happening on the first time through.
Here is the stacktrace.
java.lang.NullPointerException
at com.revature.data.postgres.CommentPostgres.getAll(CommentPostgres.java:90)
at com.revature.data.CommentDaoTest.getAllNotNull(CommentDaoTest.java:42)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:725)
at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)
at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:149)
at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:140)
at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:84)
at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(ExecutableInvoker.java:115)
at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke$0(ExecutableInvoker.java:105)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)
at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104)
at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$7(TestMethodTestDescriptor.java:214)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:210)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:135)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:66)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:151)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
at java.util.ArrayList.forEach(ArrayList.java:1259)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
at java.util.ArrayList.forEach(ArrayList.java:1259)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)
at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:107)
at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88)
at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54)
at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67)
at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:95)
at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:91)
at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:60)
at org.eclipse.jdt.internal.junit5.runner.JUnit5TestReference.run(JUnit5TestReference.java:98)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:40)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:529)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:756)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:452)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)
Please let me know if you want more files or code snippets added. Thank you for your help.

Answer 1

This line creates a new, empty Comment object:
Comment comment = new Comment();
After that line, you never call comment.setApprover(), so the approver property inside the comment object is null. This doesn't have anything to do with missing data in the database, it is a problem with the way you are initializing your Java objects.
Look at what you are doing here:
comment.getApprover().setEmpId(resultSet.getInt("approver_id"));
You're saying "take the new comment object I just created, get the approver object from it, and then set the ID of that approver". Instead your code needs to look something like this:
Approver approver = getApproverByEmpId(resultSet.getInt("approver_id"));
comment.setApprover(approver);
Where getApproverByEmpId(Integer empId) is a new method you need to create that queries the employee table, and returns an Employee object.