Minecraft C.E hacks.

NOTE: When selecting the process select Window List.

Item Morphing
Open Cheat Engine and select process javaw.exe, minecraft.exe or whatever you're using.
Get at least 3 of some block type in your quick slot.
Start a new search and search for that quantity.
Drop an item (Q).
Search for the new value.
Drop another (or pickup the old one, doesn't matter).
Search for the new value. You should only have a few now. Repeat until you only have ONE entry.
Double click to add entry.
In the bottom pane, right click and choose 'Browse this memory region'.
Exactly 8 bytes to the right of the block's quantity is the block's TYPE. Compare with the hex values found here.
To change the type, copy the DECIMAL value from here, double click on the type in the memory viewer, select 2 bytes, and paste.




Classic
Open Cheat Engine and select process javaw.exe, minecraft.exe or whatever you're using.
In minecraft, make sure you have the first block in your UI as stone.
Scan for the exact value 1.
Go to minecraft and change the first block in the UI to cobblestone.
Scan for the exact value 4.
Go to minecraft and change the first block back to stone.
Repeat step 4.
This should yield one or two addresses. Pick one (or both) and change the value to one of the following material values from this list.


Invulnerability
Open Minecraft.
Open Cheat Engine and select javaw.exe, minecraft.exe or whatever you're using.
Get your number of hearts, and double it, adding one if you have a half heart (full hearts = 20), and start a new search in CE with this value.
Get hurt a bit, or heal a bit, and recalculate your HP. Enter this value for the next search.
Repeat until one value remains. Double click to add.
Either set to a very high value (~34567), or set to 20 and freeze.
Enjoy (near) invulnerability.
Here is a video going through the process.
NOTE: If you freeze your value, do not enter/leave The Nether, this will move the address where you HP is stored, possibly leading to data corruption and crashed games. Also, you won't be invulnerable again. You can re do the above hack WHILE in The Nether, though, and it works fine.



Unbreakable Tools
Open Minecraft.
Open Cheat Engine and select javaw.exe, minecarft.exe or whatever you are using.
Equip a tool that is in perfect condition.
Find a block that is used by that tool (i.e. stone for a pickaxe, dirt for a shovel).
Destroy the block with the tool and search for a value of 1 in CE.
Do this again destroying another stone block and search for 2.
Repeat until you have only one address left.
Edit the value to something like -30000 and enjoy. You can now close Cheat Engine as these changes will persist (even across saves).


Cube of destruction
A cube of destruction is actually a n*n*n cube of tnt, that has been frozen on the TNT state and will never change back to air until the JVM changes block addresses.
Open minecraft and load/start a new game.
Collect a few of any block type (dirt recommended) and place your cube (any size, any shape).
Open Cheat Engine and select javaw.exe, minecraft.exe or whatever you are using.
Select size 'Byte'.
Search for the value of the type of block you used (3 for dirt, find other data values if you used another block type).
Destroy the cube.
Return to CE, and search again for value '0'.
Reconstruct the cube at the same exact spot.
Search again for the block's value.
Repeat placing, filtering for block type, destroying, and filtering for 0 until only a few items are on the list (i.e. 8 for a 2*2*2 cube), then select the values and click the red arrow.
Set the values to 46, and then freeze.
In game, whack a few of the TNT and run.
You will die unless you hacked your health. Before respawning, un-freeze the values, and respawn to see the damage.