Android App Memory Leak Security: Complete Prevention Guide 2025

// Secure Memory Management Implementation
public class SecureMemoryManager {
    private byte[] sensitiveData;
    private boolean isCleared = false;
    
    public void storeSensitiveData(byte[] data) {
        // Store data securely
        this.sensitiveData = data.clone();
    }
    
    public void clearSensitiveData() {
        if (sensitiveData != null && !isCleared) {
            // Securely overwrite memory
            Arrays.fill(sensitiveData, (byte) 0);
            sensitiveData = null;
            isCleared = true;
        }
    }
    
    @Override
    protected void finalize() throws Throwable {
        try {
            clearSensitiveData();
        } finally {
            super.finalize();
        }
    }
}

// Secure Activity Implementation
public class SecureActivity extends AppCompatActivity {
    private SecureMemoryManager memoryManager;
    
    @Override
    protected void onDestroy() {
        // Clear sensitive data before destruction
        if (memoryManager != null) {
            memoryManager.clearSensitiveData();
        }
        super.onDestroy();
    }
    
    @Override
    public void onTrimMemory(int level) {
        super.onTrimMemory(level);
        // Clear sensitive data on memory pressure
        if (level >= TRIM_MEMORY_MODERATE) {
            clearSensitiveData();
        }
    }
}

// Secure WeakReference Implementation
public class SecureWeakReference<T> extends WeakReference<T> {
    private final String securityToken;
    
    public SecureWeakReference(T referent, String securityToken) {
        super(referent);
        this.securityToken = securityToken;
    }
    
    public T getSecure() {
        T referent = get();
        if (referent == null) {
            throw new SecurityException("Reference expired or invalid");
        }
        return referent;
    }
    
    public boolean isValid(String token) {
        return securityToken.equals(token) && get() != null;
    }
}

// Secure Listener Management
public class SecureListenerManager {
    private final Map<String, SecureWeakReference<Listener>> listeners;
    
    public void addSecureListener(String id, Listener listener, String token) {
        listeners.put(id, new SecureWeakReference<>(listener, token));
    }
    
    public void notifyListeners(String token) {
        listeners.entrySet().removeIf(entry -> {
            SecureWeakReference<Listener> ref = entry.getValue();
            if (!ref.isValid(token)) {
                return true; // Remove invalid references
            }
            try {
                ref.getSecure().onEvent();
                return false;
            } catch (SecurityException e) {
                return true; // Remove expired references
            }
        });
    }
}