Cache Casting

A company is designing the class hierarchy for various cache implementations:

public class Cache {}

public class DiskCache extends Cache {}

public class MemoryCache extends Cache {}

public class OptimizedDiskCache extends DiskCache {}

Select all the answers that will result in a runtime exception.

(Select all acceptable answers.)

OptimizedDiskCache optimizedDiskCache = new OptimizedDiskCache();
Cache cache = (Cache) optimizedDiskCache;

MemoryCache memoryCache = new MemoryCache();
Cache cache = (Cache) memoryCache;
DiskCache diskCache = (DiskCache) cache;

DiskCache diskCache = new DiskCache();
OptimizedDiskCache optimizedDiskCache = (OptimizedDiskCache) diskCache;

OptimizedDiskCache optimizedDiskCache = new OptimizedDiskCache();
DiskCache diskCache = (DiskCache) optimizedDiskCache;

Cache cache = new Cache();
MemoryCache memoryCache = (MemoryCache) cache;

OptimizedDiskCache optimizedDiskCache = new OptimizedDiskCache();
Cache cache = (Cache) optimizedDiskCache;
DiskCache diskCache = (DiskCache) cache;

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Difficulty: Hard

Duration: 3 min

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% of candidates

0-33%

34-67%

68-100%

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Cache Casting

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