# Fixed JobQueue Implementation

The race condition occurs because multiple threads can access and modify the shared `jobs` and `results` dictionaries simultaneously without synchronization. Here's the corrected implementation using proper locking:

```python
import threading

class JobQueue:
    def __init__(self):
        self.jobs = {}
        self.results = {}
        self.lock = threading.Lock()

    def add_job(self, job_id, data):
        with self.lock:
            self.jobs[job_id] = data
        return job_id

    def process_job(self, job_id, processor):
        with self.lock:
            if job_id not in self.jobs:
                return False

            data = self.jobs[job_id]
            result = processor(data)

            # Protected by lock - safe to write
            self.results[job_id] = result

            del self.jobs[job_id]
        return True

    def get_result(self, job_id):
        with self.lock:
            return self.results.get(job_id)
```

## Key Changes Made

1. **Added a Lock**: Created `self.lock = threading.Lock()` in `__init__` to protect shared state.

2. **Protected All Shared State Access**: Wrapped all accesses to `self.jobs` and `self.results` with `with self.lock:` statements in all three methods.

3. **Ensured Atomicity**: The check-then-write pattern in `process_job` is now atomic - no other thread can modify the dictionaries while one thread is processing a job.

## Why This Fixes the Race Condition

- **Before**: Multiple threads could simultaneously read from `jobs`, write to `results`, and delete from `jobs`, causing data corruption or lost updates.

- **After**: Only one thread can execute any critical section at a time, ensuring thread-safe access to shared state.

## Usage Example

```python
import time

def simple_processor(data):
    time.sleep(0.1)  # Simulate work
    return data * 2

queue = JobQueue()
queue.add_job(1, 5)
queue.add_job(2, 10)

result1 = queue.process_job(1, simple_processor)
result2 = queue.process_job(2, simple_processor)

print(queue.get_result(1))  # 10
print(queue.get_result(2))  # 20
```