Memory

You will have a file setDomainEnv.cmd/setDomainEnv.sh under your server bin folder. this file contains

set MEM_MAX_PERM_SIZE_64BIT=-XX:MaxPermSize=512m
set MEM_MAX_PERM_SIZE_32BIT=-XX:MaxPermSize=512m

Max and Min memory values as

if "%JAVA_VENDOR%"=="Sun" (
    set WLS_MEM_ARGS_64BIT=-Xms256m -Xmx512m
    set WLS_MEM_ARGS_32BIT=-Xms256m -Xmx512m
) else (
    set WLS_MEM_ARGS_64BIT=-Xms512m -Xmx512m
    set WLS_MEM_ARGS_32BIT=-Xms512m -Xmx512m
)

Eclipse

Then, open weblogic server properties (double click at weblogic in servers view) and click "Open launch configuration". In a opened window select "Environment" and add new variable ECLIPSE_MEM_ARGS with memory params as value, e.g.:

ECLIPSE_MEM_ARGS=-Xms1024m -Xmx2048m -XX:MaxPermSize=512m