Question

Can I assign an operator symbol to a variable and use that variable for a conditional check?

char operator= '>';
int val1=10;
int val2=24;
if(val2 operator val1){

    /* some code*/

}

Why cant I use the operator variable inside conditions?

Answer 1

Code written in any programming language needs to be converted to Assembly Language. When this happens, every code statement written in High Level language gets translated to instruction / set of instructions in Middle Level equivalent i.e.
JAVA code will get translated to Machine Specific instructions in Assembly Language.

Here addition operation in following statement,

int a = a + 10;

May get converted to

ADD A 1010;

And when we try to access a variables value, it may get converted to READ instruction.

So, when you try to use ‘>’ in a variable,

char operator= '>';
int val1=10;
int val2=24;
if(val2 operator val1){

/* some code*/

}

The if statement,

if(val2 operator val1) 

will convert to an invalid instruction.
Instead of generating an equivalent for comparison of two values, it will READ ‘operator’ variable.

This will obviously, lead to wrong interpretation.

Hence, doing such thing is not allowed.

Every compiler(java , gcc etc ) may behave differently but the target is same. If you read Complier / Compilation / Execution more, you will know more.
These are some links:

http://www.coderanch.com/t/559258/java/java/java-codes-converted-assembly-JVM

Do programming language compilers first translate to assembly or directly to machine code?

Steps for Compilation of A C program.

http://www.herongyang.com/Computer-History/C-Program-Compilation-and-Execution-Process.html